My main beef with Discord servers turning into this decade's forums is a lot of useful info is locked up and not discoverable by search engines.
Discord tends to be social in a way Github is not, with lower friction to contribute. And perhaps even a better asynchronous model.
I don't discount your frustrations. Maybe a bot that can create GH issues from Discord would help. With rights to use it spread liberally around the community.
Tell people you need help getting data into Github, give them a bot so they don't have to context switch, and they'll probably surprise you.
This is one of the reasons I prefer Zulip to Discord. You get more organization by default, with all conversations happening in threads with subjects, and a tendency to create new threads for new topics. I can actually find information in conversations long afterwards, and cross-link to useful Zulip threads from GitHub or elsewhere.
This to me is by far the worst part of Discord. I'm in a few game mod specific Discord's and there is tons of info in them, but it's so hard to find and get to it might as well not even exist.