you can just do /afk and if a person sends you msg when you are in the "[AFK}" state, they get a message after send their msg to you saying that you are afk

yes but half the people dont see it and still assume youre ghosting

So your big brain idea is to have another message send after the first message that you claim they dont even read

its not just that but having something custom could also be quite cool

This would be nice