With Google locking down Android are there any viable mobile OSs, not based on Android, usable as a daily driver besides #SailfishOS?

I haven't used any of the other mobile Linux OSs besides #Sxmo for a short while.

And "viable" is of course very subjective but minimally one should be able to make and receive calls without any issues, SMS, mobile data up to 5G and VoLTE, run a Signal client¹ and browser.

¹ @Mer__edith please start working on a client for Linux phones (talk with @rubdos)

@aerique, @Mer__edith and @rubdos, why doesn't Signal work without a phone, i.e. there isn't any desktop independent client for it?
@cnx @aerique @Mer__edith There are a few reasons. The largest fraction of their user bases uses it from a phone, it's meant as a drop-in replacement for WhatsApp.
They require a phone number for registration, as a measure against (mainly) sock puppet attacks.
The fraction of users that would be happy to register with a phone number desktop-only is way too small for them to support.
@aerique @Mer__edith @rubdos they do have linux phone but they're not that good for the price. If you find any let me know.