None basically. There’s a Sony phone has LineageOS (including +microg variant) support, but it’s not ideal either.

The Linux Foundation has a mentorship programme which is really great, might be worth a look, although I am not sure how easy it is to get accepted: https://docs.linuxfoundation.org/lfx/mentorship/mentees

If you are open to building something yourself this might be an alternative (disclaimer: I just know of this project but no idea how well it works): https://www.findmycat.io/