I personally use Fedilab for Mastodon, but idk if that makes such a difference. There isn’t really a discover feature that I know off, but remember to follow not only people, but also hashtags! This’ll show you stuff you’re interested in, and then you can follow the people posting stuff you like.

You also have a local feed that shows stuff from the instance where your account is hosted, it turns handy especially if you’ve chosen an instanced themed around one of your centers of interest.