I’m working on porting Mobian to the Pixel 3a, pretty much everything works, even eSIM. The kernel dev is already working on upstreaming the patches, some are already in the next Linux release.
I’ve recently posted about the progress: https://lemmy.sdf.org/post/19600671
Updates to that post would be that eSIM does work and that the internal microphone will work very soon once the already existing patches are pushed to the git repo.
I’ve put together some notes which shod help you build an image for testing. https://git.erebion.eu/forgejo/erebion/sargo-temp
Keep in mind that some infos need updates, eSIM works, microphone works when changes are pushed in a few days.