I have a Samsung Galaxy J3 2018 (model number SM-J337W) on which I want to install my own custom AOSP ROM (because I don’t want Google or Samsung to spy on me, I’m stuck with my current phone, and my phone is not supported by LineageOS, GrapheneOS, or CalyxOS). I have managed to install ADB for Linux and unlock the bootloader, but I can’t download any TWRP binaries because my phone is not on the list of officially supported devices. I believe i’ve found the source code for TWRP on this Github page: https://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni. However, I’m not really sure how to build it. According to the code lines bellow, I believe it requires some kind of device number or code:

cd <source-dir>; export ALLOW_MISSING_DEPENDENCIES=true; . build/envsetup.sh; lunch omni_<device>-eng; mka recoveryimage

or if I’m not using a recovery partition:

cd <source-dir>; export ALLOW_MISSING_DEPENDENCIES=true; . build/envsetup.sh; lunch omni_<device>-eng; mka bootimage

Also, I am not sure whether or not if my device uses a recovery partition or not. How do I find that out on my specific device?

Also, when I open up AIDA64, then go to System -> Device, it says j3topltecs. Should I use that for my device number/code?

Also, please keep in mind that this is my very first attempt at rooting any Android smartphone so sorry if I sound like an idiot noob. I also use Linux and don’t have Windows installed.

Also, is there any way I could tell lunch (or whatever tool does the compiling) to use only a specific number of threads because if it starts compiling using all 8 threads then my PC will definitely overheat.

PS. Do I even really need TWRP? Has anyone ever managed to install a custom ROM on this specific device?