In my experience, I can’t mute on nostr:npub18m76awca3y37hkvuneavuw6pjj4525fw90necxmadrvjg0sdy6qsngq955 unless I am following the person. I recently said GM frens and got FU from one new account withe the profile name F**k. Decided to give them a minute and their next bon mot was “Eff the GM cult”.  Decided then to ditch that crap from my timeline. Couldn’t mute until I went over to nostr:npub12vkcxr0luzwp8e673v29eqjhrr7p9vqq8asav85swaepclllj09sylpugg and searched the account profile so I could mute.