Ok, eventually I got rid of spam on #damus too and I also made sure I’m not missing DMs (except for the gift-wrapped ones of course which should be the only ones you use) by adding these three relays in addition to my six wot-relays:
wss://inbox.nostr.wine
wss://relay.0xchat.com
wss://auth.nostr1.com
So far everything works fine and the experience is clean.
nostr:npub1tm99pgz2lth724jeld6gzz6zv48zy6xp4n9xu5uqrwvx9km54qaqkkxn72 does your relay transmit only DMs or are you pro-actively filtering spam?