Tell me more! There are ways to deal with DDoS. Would it help to limit access to a relay to a group of paying users? I'm working on that as I always found it weird how relays do not count at all the resources that go towards answering read queries.
Discussion
I'm not an expert on relays and only thinking out loud. Making payed relays or any other obsticle for bots will definitely help.
I find these two articles about #nostr #Privacy
They might give you some useful info