[OnePlus 3 & 3T Cross Device Development] :
Script I am using to make my LOS flying after each install/ dirty flash update:

#!/sbin/sh
#
# Script by 2Tweak
# Last modified 13-04-2019

clear 2>/dev/null
mount /system 2>/dev/null

# app list to remove
applist="
/system/app/AntHalService
/system/app/BasicDreams
/system/app/BuiltInPrintService
/system/app/Calendar
/system/app/CtsShimPrebuilt
/system/app/EasterEgg
/system/app/Email
/system/app/ExactCalculator
/system/app/Exchange2
/system/app/HTMLViewer
/system/app/Jelly
/system/app/LatinIME
/system/app/LiveWallpapersPicker
/system/app/messaging
/system/app/PhotoTable
/system/app/PrintRecommendationService
/system/app/Stk
/system/app/Terminal
/system/app/Traceur
/system/app/WallpaperBackup
/system/priv-app/AudioFX
/system/priv-app/BackupRestoreConfirmation
/system/priv-app/CallLogBackup
/system/priv-app/CNEService
/system/priv-app/CtsShimPrivPrebuilt
/system/priv-app/Contacts
/system/priv-app/DocumentsUI
/system/priv-app/Eleven
/system/priv-app/InputDevices
/system/priv-app/ManagedProvisioning
/system/priv-app/OneplusDoze
/system/priv-app/OneplusPocketMode
/system/priv-app/OneTimeInitializer
/system/priv-app/Gallery2
/system/priv-app/SharedStorageBackup
/system/priv-app/Tag
/system/priv-app/Updater
/system/priv-app/UserDictionaryProvider
/system/priv-app/VpnDialogs
/system/priv-app/WeatherProvider
/system/priv=app/WfdService
/system/media/bootanimation.zip
/system/bin/bootanimation
"

# /system/app/NfcNci >> resulting in crash on profiles setting
# /system/priv-app/SettingsIntelligence >> resulting in slow settings menu
# /system/priv-app/WallpaperCropper >> resulting in reboot at fresh install

# file list to cleanup
filelist="
/cache/*
/data/anr/*
/data/backup/*
/data/cache/*
/data/dalvik-cache/*
/data/lost+found/*
/data/tombstones/*
/data/backup/pending/*
/data/local/tmp/*
/data/system/dropbox/*
/data/system/procstats/*
/data/system/usagestats/daily/*
/data/system/usagestats/0/monthly/*
/data/system/usagestats/0/weekly/*
/data/system/usagestats/0/yearly/*
/data/system/last-fstrim
/data/system/install_sessions.xml
/data/system/uiderrors.txt
"

echo
echo "######################################"
echo "# ROM DEBLOAT SCRIPT #"
echo "######################################"

echo
echo "Shrinking ROM to the bare minimum....."
for appname in $applist
do
chmod -rf 777 $appname 2>/dev/null
rm -rf $appname 2>/dev/null
if [[ ! -e $appname ]]; then
echo - deleted $appname
else
echo - $appname still there, check permissions!
fi
done
echo "Done, unneeded apps removed!"

echo
echo "Removing junk files..................."
for filename in $filelist
do
chmod -rf 777 $filename 2>/dev/null
rm -rf $filename 2>/dev/null
done
echo "Done, junk files removed!"

echo
echo "Clearing all app caches..............."
# Clear app caches
for i in $(ls /data/data/ 2>/dev/null)
do
chmod -rf 777 /data/data/$i/cache 2>/dev/null
rm -rf /data/data/$i/cache/* 2>/dev/null
rm -rf /data/data/$i/code_cache/* 2>/dev/null
done
echo "Done, cleared all app caches!"

echo
echo "Setting log permissions read-only....."
chmod 400 /data/system/dropbox 2>/dev/null
chmod 400 /data/system/procstats 2>/dev/null
chmod 400 /data/system/usagestats/0/daily 2>/dev/null
chmod 400 /data/system/usagestats/0/monthly 2>/dev/null
chmod 400 /data/system/usagestats/0/weekly 2>/dev/null
chmod 400 /data/system/usagestats/0/yearly 2>/dev/null
echo "Done, permissions set!"

echo
echo "Adding my build.prop settings........."
grep -qxF 'My build.prop settings' /system/build.prop 2>/dev/null || echo '
######################################
# My build.prop settings #
######################################

# Disable multi user
fw.max_users=1
fw.show_multiuserui=0
fw.show_hidden_users=0
fw.power_user_switcher=0

# Disable sending usage data
ro.config.nocheckin=1

# No boot animation
debug.sf.nobootanimation=1

# Disable ring delay
ro.telephony.call_ring.delay=0
ring.delay=0

# Improve AMR codec call quality
ro.ril.enable.amr.wideband=1
ro.config.vc_call_steps=20

# Enable VoLTE and VoWiFi calling
persist.dbg.ims_volte_enable=1
persist.dbg.volte_avail_ovr=1
persist.dbg.vt_avail_ovr=1
persist.dbg.wfc_avail_ovr=1
persist.radio.rat_on=combine
persist.radio.data_ltd_sys_ind=1
persist.radio.data_con_rprt=1
persist.radio.calls.on.ims=1

# Improve network signals
persist.cust.tel.eons=1
ro.config.hw_fast_dormancy=1

# Disable automatic error
profiler.force_disable_err_rpt=1
profiler.force_disable_ulog=1

# Disable error checking
ro.kernel.checkjni=0
ro.kernel.android.checkjni=0

# Disable Strict Mode checking
persist.android.strictmode=0

# Disable logcat
logcat.live=disable

# Optimize Dalvik
dalvik.vm.dexopt-flags=v=n,o=v,m=y

# Optimize internet settings
net.tcp.buffersize.default=4096,87380,256960,4096,16384,256960
net.tcp.buffersize.wifi=4096,87380,256960,4096,16384,256960
net.tcp.buffersize.umts=4096,87380,256960,4096,16384,256960
net.tcp.buffersize.gprs=4096,87380,256960,4096,16384,256960
net.tcp.buffersize.edge=4096,87380,256960,4096,16384,256960
net.tcp.buffersize.hspa=6144,87380,524288,6144,16384,262144
net.tcp.buffersize.lte=524288,1048576,2097152,524288,1048576,2097152
net.tcp.buffersize.hsdpa=6144,87380,1048576,6144,87380,1048576
net.tcp.buffersize.evdo_b=6144,87380,1048576,6144,87380,1048576

# Use OpenDNS Family settings everywhere
net.dns1=208.67.222.123
net.dns2=208.67.220.123
net.rmnet0.dns1=208.67.222.123
net.rmnet0.dns2=208.67.220.123
net.ppp0.dns1=208.67.222.123
net.ppp0.dns2=208.67.220.123
net.wlan0.dns1=208.67.222.123
net.wlan0.dns2=208.67.220.123
net.eth0.dns1=208.67.222.123
net.eth0.dns2=208.67.220.123
net.gprs.dns1=208.67.222.123
net.gprs.dns2=208.67.220.123
' >> /system/build.prop 2>/dev/null

chmod 644 /system/build.prop 2>/dev/null
echo "- Disabled multi user mode............"
echo "- Disabled sending usage data........."
echo "- Disabled boot animation............."
echo "- Disabled ring delay................."
echo "- Improved AMR codec call quality....."
echo "- Enabled VoLTE and VoWiFi calling...."
echo "- Disabled automatic error reporting.."
echo "- Disabled error checking............."
echo "- Disabled Strict Mode checking......."
echo "- Disabled logcat....................."
echo "- Optimized Dalvik cache settings....."
echo "- Optimized internet settings........."
echo "- Use OpenDNS Family everywhere......."
echo "Done, added build.prop settings!"

echo
echo "Trimming SSD storage.................."
fstrim -v /data 2>/dev/null
fstrim -v /cache 2>/dev/null
fstrim -v /system 2>/dev/null
echo "Done, all SSD storage trimmed!"

No support, just a do it yourself.... ;))