AUTH works well but is the nuclear option. Softening auth via invite codes and access requests would help admins expand their member lists more easily
Discussion
It’s not sufficient though, maybe you whitelist a pubkey based on a topic but they only write 5% of the time on that topic
And clients are not good at segregating content, so relays need more powerful tools than just AUTH imo.
It depends on if you want topic based or people based groups, but yeah