I have the same problem as you with mastodon, I’m interested in topics not in people so the format just doesn’t make a lot of sense to me.
I’ve had very limited success with following hashtags, it sounds like a neat idea, but I’ve not found enough hashtags that I’m interested in with enough activity to make it worthwhile.
The nature of it also makes it more superficial - it’s short comments and posts on a topic rather than more in depth discussion.
In the end, I think mastodon is a really neat replacement for twitter - but I never had a twitter account for a reason, and those reasons are still there with mastodon, for me at least.