Agreeing that it's not a seamless transition in user experience from Reddit to Lemmy/kbin. But one thing that at least the instance that I'm on (kbin.social) makes easy is subscribing to various communities (or magazines, which is what they are called on kbin):
I go to the Magazines screen in kbin.social, type.in the general topic I'm interested in (in your example, cats). The search results in kbin.social bring me all of the magazines and communities that have cat in the name, and I subscribe to them all. (Meaning, I don't have to type out the full community address.)
Yes, a lot of it will be redundant and if I don't subscribe to specific communities I may miss some stuff. But I can say that now I have a ton pf.contwct that I'm interested in my "Subscribed" feed (similar to the home feed on Reddit).