Look, this is basically a UI change. None of those features are removed from backend and I hope they don't, ever. As an engineer who maintains a kind of a beefy MinIO cluster myself, I already have a bunch of complaints about the product. UI is not one of them. I really hope that this move is simply the result of a re-org that moves more people to work on real issues.
Well, the real issues won't be on the open source version. They've more or less confirmed on their slack that the open source version is in maintenance-only mode: