Have you tried Conversations(Android) or Gajim(desktop)?
Tried Gajim 3y ago, put on "something is missing" list. Don't remember exactly. There is a lot of jabber features not included in basic specification but via XEPs. Did not find a client that has all required XEPs implemented.
I cannot agree. Just try Conversations on Android and Gajim on desktop. xmpp is a solid and reliable protocol.
1. XMPP is solid. But without XEP is very limited. Client based on pure XMPP is almost unusable for people. 2. Tried to get list of supported XEPs for gajim. https://gajim.org/support/extensions is dead link - bad way to persuade me. After spending some time of googling, I have got list of supported XEPs. Will give it a chance again.