I use Signal because it’s the best balance of privacy and security vs. convenience and reliability I have found. Not self-hosted, but I’ve yet to find a self hosted alternative that is as reliable, especially since I don’t want to set up distributed servers, and it’s one of those things that “just needs to work” or people will abandon it quickly.
And the older people I’ve convinced to use it, like my mom, have had very little trouble adopting it. It helped that RCS messaging is so unreliable on my phone since Google or my carrier keep seeming to break it (likely became I use GrapheneOS), and also for those with iPhones it is way more compatible with itself vs Apple and Google refusing to implement RCS in a way that all features work between them, like message reactions. Without RCS, my mom couldn’t send me decent quality pictures of my niece all the time, and I couldn’t send nice pictures of my outfits to the girl I’m dating, LOL.
Yeah, already installed vs. may require some tweaks to get all of your hardware working, is a big one, especially with laptops since there’s so much proprietary junk in many of them.