use my script (https://github.com/ChromiumOS-Guy/SuperPatcherGSI)
DSU Sideloader to install GSI more painless then other methods like unpacking super.img and then pack it again with custom system.img but this is easer and safer
!WARNING!
DSU sideloader will not remove your current installion it will sideload a new one hence DSU Sideloader for premenent install you have to unpack your super.img file
DSU sideloader is not for you don't use it
also you can install an custom recovery please do it
(https://source.android.com/docs/core/ota/dynamic_partitions)
(https://blog.senyuuri.info/posts/2022-04-27-patching-android-super-images/)
Phone has no system partition (https://forum.xda-developers.com/t/apparently-my-phone-has-no-system-partition.4435045/)
understanding A/B (https://forum.xda-developers.com/t/help-understanding-a-b-partitions.3748003/)
OrangeFox Recovery Project (https://orangefox.download/)
TeamWin Recovery Project (https://twrp.me/)
Google GSI (https://developer.android.com/topic/generic-system-image/releases)
Ubuntu Touch GSI (https://forum.xda-developers.com/t/gsi-arm64-a-ab-ubuntu-touch-ubports.4110581/)
lineageOS GSI (https://sourceforge.net/projects/andyyan-gsi/files/)
GSI List (https://github.com/phhusson/treble_experimentations/wiki/Generic-System-Image-%28GSI%29-list)
explanation - (https://forum.xda-developers.com/t/what-are-a-only-gsis-used-for-and-why-dont-we-just-call-these-non-sar.4369919/)
SuperPatcherGSI python script (https://github.com/ChromiumOS-Guy/SuperPatcherGSI)
Android-Debloater [NO ROOT] (https://github.com/ChromiumOS-Guy/Android-Debloater)
lpmake source (https://github.com/Dargons10/lpunpack_and_lpmake)