[fsflover]

Matrix: https://matrix.org/

[balladeer]

If UX is the concern then Matrix/Riot may not fare very well.

[INTPenis]

I've been using the RiotX beta app for android last few weeks and yes it is definitely in beta, some parts just won't work. But basic chatting, joining rooms and communicating with their "fediverse" works just fine and looks very modern.