I've tried on several occasions, but I just haven't found those niches yet on Lemmy (I use it through kBin). It's kinda there but also still kinda empty one you go outside the more general feeds.

The sad reality is a lot of reddit operated off the minority of power users. And those power users are either still on Reddit, went somewhere else entirely (maybe Discord), or are "retired". The network effect will take a while to overcome, if it's overcome at all.