the reason there arent relays is that theyre expensive to run (150$+ a month, if you rent, and the cost seems to scale linearily with the amount of users on the network), i saw a blog about someone who hosted one briefly (https://whtwnd.com/bnewbold.net/entries/Notes on Running a Full-Network atproto Relay (July 2024), and it isnt even that hard to setup, it’s mostly just the cost.

Also, relay’s aren’t technically needed, you could make an appview that pulls from pds’s directly.