Years ago, I set up a Matrix server. I got some people to migrate, but ultimately even my husband stopped using it because the UI and accessibility of all the applications was so poor (and he has very bad eyesight, so this was a dealbreaker)
Looking for another alternative, I ended up with Telegram. It was pretty open, easy to work with, had great UI and even a ton of funny stickers and emojis, so I got nearly all my friends to migrate. I did NOT go for Signal because I do not need end-to-end encryption all the time, and having all the same conversations available on my desktop as well as on my phone was important, and still is. Unfortunately, it's also run by a severe weirdo.
So yeah, I'm not really sure what to use now.