I agree that it should be easier. The problem comes from the element mobile apps migrating to a new registration flow that homeservers other than synapse haven't finished implementing yet.
If you use continuwuity, and it's few users, you could create users via the admin room. Then login should work. Still, annoying workaround.
And yeah, setting up LiveKit is a bit annoying. Maybe someone'll make a compose flow that combines all of them, but I am too lazy rn, and I haven't seen any from anyone else yet.
Didn't Vivaldi? I don't really use them cause I mostly avoid non-FOSS software, but I seem to remember them announcing they'd be keeping support.