[ONE General] ilmich:
I've finally resized system partition of my opo with sfdisk method.

This is the previous partition table layout

The backup GPT table is corrupt, but the primary appears OK, so that will be used.
label: gpt
label-id: 98101B32-BBE2-4BF2-A06E-2BB33D000C20
device: /dev/block/mmcblk0
unit: sectors
first-lba: 34
last-lba: 122142686
table-length: 32
sector-size: 512

/dev/block/mmcblk0p1 : start= 16384, size= 131072, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=A4163A7D-40EF-DACD-CB27-B41B1C3680D0, name="modem", attrs="GUID:60"
/dev/block/mmcblk0p2 : start= 147456, size= 1024, type=DEA0BA2C-CBDD-4805-B4F9-F428251C3E98, uuid=CDA708C3-6D7F-FB73-B04F-53942882A4CD, name="sbl1"
/dev/block/mmcblk0p3 : start= 148480, size= 64, type=D4E0D938-B7FA-48C1-9D21-BC5ED5C4B203, uuid=450293A5-F643-66A1-D45E-B257002D9EE0, name="dbi"
/dev/block/mmcblk0p4 : start= 163840, size= 64, type=20A0C19C-286A-42FA-9CE7-F64C3226A794, uuid=8D963267-40DB-1492-1264-9D5440BAC6B7, name="DDR", attrs="GUID:60"
/dev/block/mmcblk0p5 : start= 180224, size= 2048, type=400FFDCD-22E0-47E7-9A23-F16ED9382388, uuid=875E8321-517B-B549-5B7C-1F9BB6937A71, name="aboot"
/dev/block/mmcblk0p6 : start= 182272, size= 1000, type=098DF793-D712-413D-9D4E-89D711772228, uuid=7A8956C5-9A84-724D-8B84-ADF4904880B3, name="rpm"
/dev/block/mmcblk0p7 : start= 196608, size= 32768, type=20117F86-E985-4357-B9EE-374BC1D8487D, uuid=41078EA3-E34B-D66D-FC19-2D7F27273119, name="boot", attrs="GUID:60"
/dev/block/mmcblk0p8 : start= 229376, size= 1000, type=A053AA7F-40B8-4B1C-BA08-2F68AC71A4F4, uuid=850EB26D-0AEE-84CD-6A32-85452E25864C, name="tz"
/dev/block/mmcblk0p9 : start= 230376, size= 2048, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=7EE1F330-E8B9-A95E-D79E-21D9C6B282B2, name="pad"
/dev/block/mmcblk0p10 : start= 232424, size= 3072, type=EBBEADAF-22C9-E33B-8F5D-0E81686A68CB, uuid=A7DED425-8EED-C76A-E59D-DCBABE5CADAA, name="modemst1"
/dev/block/mmcblk0p11 : start= 235496, size= 3072, type=0A288B1F-22C9-E33B-8F5D-0E81686A68CB, uuid=687992DC-BA97-947B-9C23-840835630D67, name="modemst2"
/dev/block/mmcblk0p12 : start= 238568, size= 20480, type=EBBEADAE-22C9-E33B-8F5D-0E81686A68CC, uuid=4AD4C6BB-A812-5B31-911F-52D01C092FC7, name="oppodycnvbk"
/dev/block/mmcblk0p13 : start= 259048, size= 20480, type=0A288B1E-22C9-E33B-8F5D-0E81686A68CC, uuid=2152C074-E255-BA44-5759-5623AB70A3E6, name="oppostanvbk"
/dev/block/mmcblk0p14 : start= 294912, size= 2711552, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=B17FA16F-3B1D-8D12-329D-88B49B096554, name="system", attrs="GUID:60"
/dev/block/mmcblk0p15 : start= 3006464, size= 65536, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C9, uuid=C6713738-49DB-64A9-55D0-A007EC87B868, name="persist", attrs="GUID:60"
/dev/block/mmcblk0p16 : start= 3072000, size= 1048576, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699CA, uuid=FECD51F4-9A16-5B2A-B3EC-57F158ADBC2D, name="cache", attrs="GUID:60"
/dev/block/mmcblk0p17 : start= 4120576, size= 32768, type=20117F86-E985-4357-B9EE-374BC1D8487D, uuid=F255D8D9-53B3-5F61-E89D-2CC2E086634A, name="recovery", attrs="GUID:60"
/dev/block/mmcblk0p18 : start= 4153344, size= 3072, type=638FF8E2-22C9-E33B-8F5D-0E81686A68CB, uuid=9920EC5A-2042-C6EC-A97C-E934D1714F0B, name="fsg", attrs="GUID:60"
/dev/block/mmcblk0p19 : start= 4161536, size= 2, type=57B90A16-22C9-E33B-8F5D-0E81686A68CB, uuid=CCBEF8D1-726E-DD15-64EC-F8E8D58186E5, name="fsc"
/dev/block/mmcblk0p20 : start= 4161538, size= 16, type=2C86E742-745E-4FDD-BFD8-B6A7AC638772, uuid=DCB6AA3E-6BFB-EAC4-00D7-C23CFD6B864D, name="ssd"
/dev/block/mmcblk0p21 : start= 4161554, size= 2048, type=20117F86-E985-4357-B9EE-374BC1D8487D, uuid=DDD85AEF-D870-2522-EDD0-07B032BDADB1, name="misc"
/dev/block/mmcblk0p22 : start= 4163602, size= 32768, type=004A6838-062A-44DF-8152-4F340C052255, uuid=0B8F929B-3678-E384-4CCB-C012FF779884, name="LOGO"
/dev/block/mmcblk0p23 : start= 4196370, size= 65536, type=004A6838-062A-44DF-8152-4F340C052256, uuid=868365F1-3B07-C3BE-66D4-5EC3E2088005, name="DRIVER"
/dev/block/mmcblk0p24 : start= 4261906, size= 65536, type=004A6838-062A-44DF-8152-4F340C052251, uuid=D6519904-8858-2082-3851-C81CF232080C, name="reserve1"
/dev/block/mmcblk0p25 : start= 4327442, size= 32768, type=004A6838-062A-44DF-8152-4F340C052252, uuid=BE1B4E93-CF2C-1F75-B7E9-ED21B264EAF3, name="reserve2"
/dev/block/mmcblk0p26 : start= 4360210, size= 16384, type=004A6838-062A-44DF-8152-4F340C052253, uuid=C83ECC72-66E2-BB18-7D3D-537337A2B26B, name="reserve3"
/dev/block/mmcblk0p27 : start= 4376594, size= 131072, type=004A6838-062A-44DF-8152-4F340C052254, uuid=661A7058-65A6-2522-899F-E5EF7725C1DB, name="reserve4"
/dev/block/mmcblk0p28 : start= 4521984, size= 117021080, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C8, uuid=18B53706-6A52-227C-C44B-2A8A45B66791, name="userdata", attrs="GUID:60"
/dev/block/mmcblk0p29 : start= 121552896, size= 589791, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=65851334-7F65-7F54-1CC9-201110003C16, name="grow"

after a couple of adb shell commands this is the result

label: gpt
label-id: 98101B32-BBE2-4BF2-A06E-2BB33D000C20
device: /dev/block/mmcblk0
unit: sectors
first-lba: 34
last-lba: 122142686
table-length: 32
sector-size: 512

/dev/block/mmcblk0p1 : start= 16384, size= 131072, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=A4163A7D-40EF-DACD-CB27-B41B1C3680D0, name="modem", attrs="GUID:60"
/dev/block/mmcblk0p2 : start= 147456, size= 1024, type=DEA0BA2C-CBDD-4805-B4F9-F428251C3E98, uuid=CDA708C3-6D7F-FB73-B04F-53942882A4CD, name="sbl1"
/dev/block/mmcblk0p3 : start= 148480, size= 64, type=D4E0D938-B7FA-48C1-9D21-BC5ED5C4B203, uuid=450293A5-F643-66A1-D45E-B257002D9EE0, name="dbi"
/dev/block/mmcblk0p4 : start= 163840, size= 64, type=20A0C19C-286A-42FA-9CE7-F64C3226A794, uuid=8D963267-40DB-1492-1264-9D5440BAC6B7, name="DDR", attrs="GUID:60"
/dev/block/mmcblk0p5 : start= 180224, size= 2048, type=400FFDCD-22E0-47E7-9A23-F16ED9382388, uuid=875E8321-517B-B549-5B7C-1F9BB6937A71, name="aboot"
/dev/block/mmcblk0p6 : start= 182272, size= 1000, type=098DF793-D712-413D-9D4E-89D711772228, uuid=7A8956C5-9A84-724D-8B84-ADF4904880B3, name="rpm"
/dev/block/mmcblk0p7 : start= 196608, size= 32768, type=20117F86-E985-4357-B9EE-374BC1D8487D, uuid=41078EA3-E34B-D66D-FC19-2D7F27273119, name="boot", attrs="GUID:60"
/dev/block/mmcblk0p8 : start= 229376, size= 1000, type=A053AA7F-40B8-4B1C-BA08-2F68AC71A4F4, uuid=850EB26D-0AEE-84CD-6A32-85452E25864C, name="tz"
/dev/block/mmcblk0p9 : start= 230376, size= 2048, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=7EE1F330-E8B9-A95E-D79E-21D9C6B282B2, name="pad"
/dev/block/mmcblk0p10 : start= 232424, size= 3072, type=EBBEADAF-22C9-E33B-8F5D-0E81686A68CB, uuid=A7DED425-8EED-C76A-E59D-DCBABE5CADAA, name="modemst1"
/dev/block/mmcblk0p11 : start= 235496, size= 3072, type=0A288B1F-22C9-E33B-8F5D-0E81686A68CB, uuid=687992DC-BA97-947B-9C23-840835630D67, name="modemst2"
/dev/block/mmcblk0p12 : start= 238568, size= 20480, type=EBBEADAE-22C9-E33B-8F5D-0E81686A68CC, uuid=4AD4C6BB-A812-5B31-911F-52D01C092FC7, name="oppodycnvbk"
/dev/block/mmcblk0p13 : start= 259048, size= 20480, type=0A288B1E-22C9-E33B-8F5D-0E81686A68CC, uuid=2152C074-E255-BA44-5759-5623AB70A3E6, name="oppostanvbk"
/dev/block/mmcblk0p14 : start= 113573888, size= 7979008, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=B17FA16F-3B1D-8D12-329D-88B49B096554, name="system", attrs="GUID:60"
/dev/block/mmcblk0p15 : start= 3006464, size= 65536, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C9, uuid=C6713738-49DB-64A9-55D0-A007EC87B868, name="persist", attrs="GUID:60"
/dev/block/mmcblk0p16 : start= 3072000, size= 1048576, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699CA, uuid=FECD51F4-9A16-5B2A-B3EC-57F158ADBC2D, name="cache", attrs="GUID:60"
/dev/block/mmcblk0p17 : start= 4120576, size= 32768, type=20117F86-E985-4357-B9EE-374BC1D8487D, uuid=F255D8D9-53B3-5F61-E89D-2CC2E086634A, name="recovery", attrs="GUID:60"
/dev/block/mmcblk0p18 : start= 4153344, size= 3072, type=638FF8E2-22C9-E33B-8F5D-0E81686A68CB, uuid=9920EC5A-2042-C6EC-A97C-E934D1714F0B, name="fsg", attrs="GUID:60"
/dev/block/mmcblk0p19 : start= 4161536, size= 2, type=57B90A16-22C9-E33B-8F5D-0E81686A68CB, uuid=CCBEF8D1-726E-DD15-64EC-F8E8D58186E5, name="fsc"
/dev/block/mmcblk0p20 : start= 4161538, size= 16, type=2C86E742-745E-4FDD-BFD8-B6A7AC638772, uuid=DCB6AA3E-6BFB-EAC4-00D7-C23CFD6B864D, name="ssd"
/dev/block/mmcblk0p21 : start= 4161554, size= 2048, type=20117F86-E985-4357-B9EE-374BC1D8487D, uuid=DDD85AEF-D870-2522-EDD0-07B032BDADB1, name="misc"
/dev/block/mmcblk0p22 : start= 4163602, size= 32768, type=004A6838-062A-44DF-8152-4F340C052255, uuid=0B8F929B-3678-E384-4CCB-C012FF779884, name="LOGO"
/dev/block/mmcblk0p23 : start= 4196370, size= 65536, type=004A6838-062A-44DF-8152-4F340C052256, uuid=868365F1-3B07-C3BE-66D4-5EC3E2088005, name="DRIVER"
/dev/block/mmcblk0p24 : start= 4261906, size= 65536, type=004A6838-062A-44DF-8152-4F340C052251, uuid=D6519904-8858-2082-3851-C81CF232080C, name="reserve1"
/dev/block/mmcblk0p25 : start= 4327442, size= 32768, type=004A6838-062A-44DF-8152-4F340C052252, uuid=BE1B4E93-CF2C-1F75-B7E9-ED21B264EAF3, name="reserve2"
/dev/block/mmcblk0p26 : start= 4360210, size= 16384, type=004A6838-062A-44DF-8152-4F340C052253, uuid=C83ECC72-66E2-BB18-7D3D-537337A2B26B, name="reserve3"
/dev/block/mmcblk0p27 : start= 4376594, size= 131072, type=004A6838-062A-44DF-8152-4F340C052254, uuid=661A7058-65A6-2522-899F-E5EF7725C1DB, name="reserve4"
/dev/block/mmcblk0p28 : start= 4521984, size= 109051904, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C8, uuid=18B53706-6A52-227C-C44B-2A8A45B66791, name="userdata", attrs="GUID:60"
/dev/block/mmcblk0p29 : start= 121552896, size= 589791, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=65851334-7F65-7F54-1CC9-201110003C16, name="grow"

the most relevant part

/dev/block/mmcblk0p14 : start= 113573888, size= 7979008, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, uuid=B17FA16F-3B1D-8D12-329D-88B49B096554, name="system", attrs="GUID:60"
/dev/block/mmcblk0p28 : start= 4521984, size= 109051904, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C8, uuid=18B53706-6A52-227C-C44B-2A8A45B66791, name="userdata", attrs="GUID:60"

now my system partition is located after userdata partition with a size of around 3,8Gb

With this method , the other partitions are untouched, no need to wipe/restore :)

EDIT: flashed latest official lineageos and it works, but by default it creates an ext4 filesystem with size of 1,3G. In order to use the new full size of partition resize2fs is neededthanks to this addon.d script created by @osmosis filesystem are now resized correctly.

bacon:/ $ df -h
Filesystem Size Used Avail Use% Mounted on
tmpfs 1.3G 760K 1.3G 1% /dev
tmpfs 1.3G 0 1.3G 0% /mnt
tmpfs 1.3G 0 1.3G 0% /apex
/dev/block/mmcblk0p14 3.7G 956M 2.8G 25% /