Matchmaking is not broken or bugged. It's working as intended.

If you're tired of having new players, griefers, leavers or highly skilled sweats in your lobbies, then you should uninstall and play other games. If you look at Dota 2 mm, it's actually a pretty good mm system, but they're intentionally not implementing it so they can gather data. If you're not willing to be a test subject for their playtest matchmaking system, then you should just uninstall for now and come back when they add a proper matchmaking system. The matchmaking is just going to get worse as pools become smaller with the declining playerbase and adding back ranked won't magically improve the mm.

It is okay for the game to eventually have just a small group of 500-1k players who are willing to playtest despite bad match quality if that's what Valve wants.