Just because everyone you know uses it, doesn't mean they can't use something else with you, maybe even understand for themselves why they shouldn't use Meta.

And it's very easy to do: you make a message for everyone you have as contact and tell them that whoever wants to continue to talk with you can continue doing so on signal, simplex, matrix, or whatever, explaining why you made this decision(meta bad, blah, blah) and tell them that in one month you'll delete your meta account(s).

At the end of that month, you do it. Remove any trace and very important: DON'T GO BACK on your decision(1 week, 1 month, 1 year) after. Whoever wants to talk, will do so wherever you told them to find you. Those that don't, well... they won't. And you'll also find out who actually cares enough to talk with you.

Talking from experience.