Snikket is easy to host in a docker container. You would have your own internet messenger for friends and family. Snikket is based on the xmpp protocol thats been around for 20 years, is tried and tested and very lightweight and does take very few resources on your server. things like Nintendo’s messenger and WhatsApp are xmpp based).
I use conversations on android as well. I think it’s the best app for android. You can ask in the conversations support channel for help, there are very knowledgeable people around:
xmpp:conversations@conference.siacs.eu?join