NIP19 nprofiles with a relay entry are not a solution -- they just resurrect the Mastadon/Matrix problem.
It doesn't resurrect the Mastodon/Matrix problem. The fact that you can have mulitple relays embedded in the nprofile is a huge win over Mastodon, where your identity (that you don't own) is stuck on one single instance that can ban you at any time. nprofile is good enough.