Hi OP, I am in a similar situation as you were so I wonder which solution you chose at the end and if you are happy with it?

I recently migrated from Github to Codeberg and it was super easy. You can also backup your code automatically from Codeberg to Github just in case.

CalyxOS still provides extended support for Pixel 4a until August 2024.

I second using a preconfig for Hyprland if you want to have something fancy and usable out of the box. You can build on top of that.

That’s already possible either by using a custom ROM or by connecting to a PC and using adb.