FWIW you can follow hashtags in mastadon If you know where to look you can see trending hashtags In other fedi clients (particularly firefish) you can configure antennae and channels to give you the ability to have pre-set feed filters and focuses (e.g. search by hashtag, keyword/subject, etc) You can also curate lists (can include people you don’t follow if you don’t want) in case you want to look at what the law or history or cycling people on fedi are talking about just now. Often when I want to change subject I’ll check to see what #lawFedi or #histodon or #biketooter have to offer today
If that sounds a bit like rolling your own algorithms, that’s probably because it sort of is