DM inbox relay ? Like a relay that sends you DMs ? only ones i know that does that if that’s what you mean is nostr:npub18kzz4lkdtc5n729kvfunxuz287uvu9f64ywhjz43ra482t2y5sks0mx5sz ‘s nostr.wine and nostr:npub1creatr06r4vr7rzx22f4kawdfj82yt09vw5rqw0kan8sr43h608s3dfeh6

nostr.wine one reminds you in dms that you’re subscription is ending and the creatr one lets you know when someone just subbed to you

but then again i might not understand what you’re asking