Why not make the server fire the client to freeze everyone? It would still be exploitable either way, as the player has network ownership of their character.
Would freezing everything except players on the server and firing all clients to anchor work? Unsure of if this is the most optimal way or not, but it should work if you’re freezing the whole server.
You can send player’s position over remote from server and then anchor player in that specific position, you can also send tick() and based off calculations get the position yourself, but first one is probably the easiest one