Internet forums are disappearing because now everything is Reddit and Discord. And that's worrying.
(www-xataka-com.translate.goog)
I set up their accounts
Setup is the hardest part. Syncing multiple devices and device migration are also hard. I'll bet you're going to act as tech support every time they get a new phone. That's fine for your family, but it's hardly going to scale.
The performance issues show up when dealing with large groups syncing between instances. You might just not be using it that way, but that's what needs to work seamlessly for a viable substitute for Discord.