I have recommended one friend to take a break from the game in the past. They were a very hardcore grinder and it got to the point that they were forcing themselves to meet weekly caps in the game even though they no longer enjoyed the content. Pretty much every time something new was released they had nothing but negative things to say about it yet they kept playing and grinding it out anyways.

They eventually decided to break on their own and seem much happier now when I talk to them so I think it was the right move.

I don't think it's justified to tell someone to stop playing for being bad. Tell them they need to improve or stay out of challenging content until they improve, sure.
But at the end of the day there's a lot of story content or solo things like crafting a player can enjoy even if they are low skilled.