@MichaelPorter several members of my family (including me) don't use Facebook and there's no one channel through which we all communicate. I worried about it at first. But one of my brothers who left Facebook before me said: if it's important, they'll contact you. If not, it's usually okay if you don't see the Facebook posts.
Old-fashioned phone calls and text messages have become a thing again in my family, and I quite like it.
It would be nice to have a single platform we all agree on where we can have a group chat, but I have a big family and it hasn't happened yet. So I try to be chill about it, and reach out to people individually more than I used to.