They’ll kick dissident mods out, install their own, and just reopen the subs like nothing happened. There’s precedent of that happening I believe (although for much more reasonable reasons, like mods going rogue for stupid or anti-free speech stuff).
That is absolutely what is going to happen. They cannot do it for all 3k subreddits right away, but they are going to go full on martial law and get the bigger ones up asap.