Naven
Answers
How do I stop somebody messaging me?
Block them. On Naven that is done from the conversation, takes one confirmation, and is silent — the other person is not told. It hides their messages and their reactions together.
Blocking is the one safety control that does not require anybody to agree with you: no report to file, no moderator to convince, no waiting. It should be the first thing anybody reaches for and it needs no justification.
A block that hides messages but leaves reactions is a half-measure, because a reaction is still a way to poke at somebody. Naven hides both.
Settings lists everybody you have blocked, with a way back if you change your mind.