It’s definitely best to meet people where they are. Discord is more user friendly for a lot of people, but something like a signal/instagram group could work depending on your group size.

If you are interested in Matrix, I am currently running one for a local security conference, and can answer some questions. I have it configured to automatically add you to rooms when you make an account. You can signup here: https://matrix.carolinacon.org/ . Or read my matrix info blurb here: https://carolinacon.org/coms.html