Do you mean quit paying to play chess? Quit trying to compete with the goal of a professional? Otherwise if not based on enjoyment there will never be any other reason to quit especially based off stats.
I mean to quit playing chess in general. How bad should you be when you should stop just playing chess. Not "should you quit chess if you don't enjoy it anymore?" That's not the question I'm asking.
The question I'm asking is "At what point should you quit chess because you're just bad at it?" That's the question I'm asking, nothing to do with fun or enjoyment but level or lack of skill.
You only want answers that have to do with a lack of skill ... But the truth is only you can set that marker, that goal post. No one from the Internet can set it for you. How skilled do you want to become? Is not being skilled enough enough reason for you to stop playing chess? Then by all means stop. Otherwise just keep playing.
How could a random internet person tell you what to think? We are not in your head.