Simple answer, you have to build your community. Start by searching #hashtags for topics that interest you. Hashtags are king on Mastodon. They can lead you to interesting people to follow. Next, start looking at your local and federated feeds to see who is discussing what, and follow those that interest you. Also, use #hashtags in your responses to make your stuff findable.
Hope this helps.
I tried it in the past too and agree it was hot garbage. But I came across this thread yesterday and decided to give it another look. And I’m impressed, to be honest. It’s way better than it used to be. It’s strange to me that Apple is making one of the better music apps for Android, but here we are.