Myrecommendations is probably to host a next cloud instance. Does all the standard ‘cloud stuff’. File, contact, calendar sync, plus a bunch if other stuff if you want to add it via plugins. If you’re patient, and a single use you can host it on basically anything. If you decide you want to add users or have a faster site, you can go down the route of sorting out faster hardware or better specs and suck.

A Yes, if you know what you are doing. Here is chat running live to show it can be done: https://fruitchattest.click/client.html

Lol, how helpful. Also no clients so basically a non starter for almost everyone.

What makes this any better than IRC?