The more relays you have, generally speaking, the worse your experience gets because you have to make connections and write and read data to every single one of them. I had 40 about 2 months ago and i...
I agree; having too many relays is an issue for clients. Relay like nostr.wine are good to workaround this as they themself connect to multiple relays with you only connecting to one. It is however a centralizing force as they are choosing the relay they connect to. The ideal would be a class of relays (paid likely as it would be quite ressource consuming) that you connect to and that you can configure to connect to a list of relay you choose.