I know these apps but none of them is as good as standard notes in my opinion. Notesnook seems fine but I don’t like fact that it is based in Pakistan. I used Joplin before buying a sub for standard notes so I know it.
Currently I have also subscription on Crypt.ee for photos but there is also a notes app integrated. Maybe I’ll start using it. Developer of cryptee was very active on reddit and he seems like a man who values privacy and security.
But I hope that simply proton will not force the migration of standard notes accounts to proton accounts and for old users everything will be as before.