This! Debian with Gnome or others is the answer. Take an afternoon to make it yours, then forget it. You can use backported kernels on Debian, to support newer hardware. Try this or upgrade to Debian 13 right now by changing the sourcefile to trixie instead of bookworm. Note : if you use Gnome, let gnome-software handle the updates for you (there’s an equivalent for kde). If you use others, configure unattented-upgrades for automatic updates.
Yes, there will still be the aosp repository as open-source. It will have some lag, but still there. Thus said, Google has moved a lot of things into the Google Play services over the years (closed sources). So, who knows what’s next! Let’s praise that some companies inject money / devs into postmarketos!