Some clients (like nostrudelfor desktop/web and Amethystfor Android) make a good job at showing clear separation for different kinds (Public Inbox, DMs, Private Relays, Search realys, etc).
As for a list of top relays, that's probably gonna be a matter of trial and error.
P.S. For general use I go with nostr.wine, relay.primal.net and relay.damus.io. For DMs, inbox.nostr.wine. On Android I also use Citrine as a local relay.
I think relays remmain a "black box" - no idea how to optimize them. Somewhere along the way, Nostr will need some documentation and recommendations on this topic.
An important post, I've been trying to search for it for a long time, but it seems that each relay has its own unique feature and cannot be combined with any other.
Yup, it's like a recipe, you need the right mix of relays. One suggestion I heard was to add the relay from every major client... not sure if that is a good approach or not.
nostr.wine,relay.primal.netandrelay.damus.io. For DMs,inbox.nostr.wine. On Android I also use Citrine as a local relay.