Here you will find statistics of the main relays to connect. And more

stats.nostr.band

For relays I recommend using maybe a handful of paid ones and the rest public probably. Over time though you'll find people whom you get along with. Here's a website for relays.

https://nostr.watch/relays/find

You'll see which ones are pay for, which are free, and probably alot more useful info if you bother going down that rabbit hole!

I use atlas.nostr.land and the ones which nostr.wine provides too. Bunch of other's too :)