What I personally like about RxDB is that it also works completely offline. However, I don't really understand encryption: As far as I understood, it encrypts on the client side with the db passwort which is sent to the server.

Another issue is Authorization and Authentication, I could not find a good solution for me for CouchDB. Couchbase seems to have better solutions for this but the premium plan seems really expensive and as far as I understood you need a "server" and a "sync server" which don't have low system requirements, at least for me.