Newbie Questions: 1. Finding topics and 2. does federation imply smallness

I'm assuming this instance will only host some topics, which is all good. (Thank you for doing this at all!)

1. How do I find topics I'm interested in? For example, I liked r/shortcuts but don't know where I'd find that in the fediverse.

2. If topics are hosted at many different instances, then even if technically anyone can participate in ones hosted elsewhere, does that imply that they'll all have their own version of r/funny etc? And they'll never achieve as much scale?

(I do realize that reddit also allowed for that redundancy, and it worked just fine... I guess I'm wondering how that challenge/opportunity PLUS some aspect of tribalism would play out...)

Cheers!