X’s mute feature is the quiet version of privacy.
I mean yeah it’s frustrating to be on the receiving end of it, but its a core part of how people manage their social media space without the confrontation of an outright block. If you think you got muted the best move is usually to just stop tagging and replying that person, atleast for a while. If you eventually use a tool to clean up your old mentions or replies to them, you might find that they ‘unmute’ you later when the feed noise dies down?