For you, I suggest sticking to Discord. I am of the mind that your effort should be focused on your community instead of enforcing a FOSS philosophy upon a group that may not have any interest in doing so.
If you are creating a new community, this is a different conversation, of course.
When I was using Librewolf maybe 4 years ago, it was never up to date with Firefox. I thought it could be a potential security risk, sometimes it took months to incorporate Firefox security updates. Has that improved recently?