I'm not sure how to word this properly. I followed like 4 different Peertube communities. Looking at the Communities drop down at the top I don't know really which one is local, which one has the most users, etc. Is there a way to like add weight so that the Peertube with the most comments or something is first?

Not sure if this is a good idea or not, but this would help find folks that want to just participate in a community find the one they want. Normally that's the biggest and most active.

which one has the most users

Peertube communities will show members, same as any other community.

I'm referring to on piefed.social, the communities drop down at the top of the page. Example image added.

I use personal feeds with similar communities for that use case

IMO weighing by (local instance) rating would be great as well.

But I feel you. If I open the Communities dropdown and start typing "peert"... there's just a bunch of stuff coming up. Some have domains added, some don't and the only difference is the "T" in it is uppercase. I'll always end up either hovering over the names, or long-pressing them on mobile to find the correct one. And I have to remember which ones I prefer. Similar issue with topics like "Technology".