Discord isn’t a good alternative, it’s not the same type of social media site. Discord is more of a chatroom aggregator, while Reddit is more of a forum aggregator. While Reddit technically supports chats and Discord technically supports threads, in both cases they’re clunky and not the main point of the site.
Unfortunate but predictable. Reddit and u/spez have decided that third-party apps are going to die, and nothing is going to stop them. The “talks” they were offering to interested devs were always just a show, as this clearly demonstrates.