[Android Software/Hacking General [Developers Only]] vp1117:
Thanks for finding the time to answer lebigmac.

Of course I know that all components of super have shared_blocks feature. I did check it dozens of times in linux and when I eventually failed to remove this feature in linux I turned to your script thinking that maybe when operating in android environment the goal could be reached more easily. Vain hopes.

For the sake of time I just ran all commands manually using adb shell, here's the output:

Z:\android\adb>adb shell
RMX3195:/ # ls /dev/block/by-name
boot flashinfo logo mmcblk0boot0 ocdt para scp1 sspm_2 vbmeta_system
boot_para frp md1img mmcblk0boot1 oppo_custom persist scp2 super vbmeta_vendor
cache gz1 md_udc mmcblk0rpmb opporeserve1 proinfo sec1 tee1
cdt_engineering gz2 metadata nvcfg opporeserve2 protect1 seccfg tee2
dtbo lk misc nvdata opporeserve3 protect2 spmfw userdata
expdb lk2 mmcblk0 nvram otp recovery sspm_1 vbmeta
RMX3195:/ # dd if=/dev/block/by-name/super of=/data/local/tmp/super.img
RMX3195:/ # cd /data/local/tmp
RMX3195:/data/local/tmp # systemrw_1.32/tools/lpunpack super.img
RMX3195:/data/local/tmp # ls
my_carrier.img my_engineering.img my_preload.img my_stock.img super.img vendor.img
my_company.img my_heytap.img my_product.img odm.img system.img
my_company.txt my_manifest.img my_region.img product.img systemrw_1.32
RMX3195:/data/local/tmp # tune2fs -l my_company.img
tune2fs 1.45.4 (23-Sep-2019)
Filesystem volume name: /my_company
Last mounted on: /my_company
Filesystem UUID: b66db7ed-4cc5-4c7f-a0cd-b6800dfaee53
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: ext_attr dir_index filetype extent sparse_super large_file huge_file uninit_bg dir_nlink extra_isize shared_blocks
Filesystem flags: signed_directory_hash
Default mount options: user_xattr acl
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
...
RMX3195:/data/local/tmp # e2fsck -yf -E unshare_blocks my_company.img > my_company.txt
e2fsck 1.45.4 (23-Sep-2019)
RMX3195:/data/local/tmp # cat my_company.txt
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/my_company: 14/16 files (0.0% non-contiguous), 13/25600 blocks
RMX3195:/data/local/tmp #
RMX3195:/data/local/tmp # tune2fs -l my_company.img
tune2fs 1.45.4 (23-Sep-2019)
Filesystem volume name: /my_company
Last mounted on: /my_company
Filesystem UUID: b66db7ed-4cc5-4c7f-a0cd-b6800dfaee53
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: ext_attr dir_index filetype extent sparse_super large_file huge_file uninit_bg dir_nlink extra_isize shared_blocks
Filesystem flags: signed_directory_hash
Default mount options: user_xattr acl
Filesystem state: clean

To clarify: my intention is not to tell you the script doesn't work. It just isn't quite suitable for specific model of realme phone. I do not have knowledge enough to claim that unremovable shared_blocks is the reason why I do not get RW on realme c25s. I just wanted to share with you that sometimes things are not that easy as they seem :)