Two things:

- Check your relays lists. I see you don't have DM relay and search relays. I am surprised you are receiving any DM at all. Since the app cannot search because you don't have relays there, user tagging might not be working. On your regular llist, re using some relays that don't exist anymore like relay.nostr.bg

- See if the notification tab is marked for Global, instead of All Follows (or any other list) at the top bar.