>* Is it the YouTube algorithm's fault? Or viewer preferences? I think YouTube would be happy to recommend the videos to more people if more people watched them.*
I always got garbage even if it suggested things I wanted to watch too.
The best way is to disable suggestions completely and then just make a note of your favourite channels. That way you get a completely blank landing page and are forced to search out exactly what you want every time.
You can disable suggestions and still subscribe to channels, I'd argue that's the easiest path while still keeping what you're actually interested in. If you have 200+ subscribed channels over the years it's less good, I'd just unscribe if you're not interested in it.