Both of these thoughts were addressed in the latest Godot Tomorrow Stream by Emi. Specifically that moving away from GitHub would be moving away from the community. Though they already use a few other git hosts (he mentioned which ones in the video). I’d think Discord would be the same issue. The dev chat is on RocketChat instead of Discord. But people come to what they’re comfortable with.
While I share the concerns with both GitHub and Discord, that’s where the people are - and it seems like that’s part of the reality that needs to be dealt with.
Personally, I’ve been using GitLab again for a professional Godot project lately (because that’s what they chose), and I’m quite enjoying it over GitHub. There are a lot of little quality of life improvements I enjoy. But I’ve kept all my plugin repos on GitHub because I know it is more likely to outlast GitLab in longevity because Microsoft owns it.