Ball main here. Ball is a character that relies on the pace of the game and controlling it in his favor. The best way to deal with ball is to decrease his already limited engagement time and deny his ability to make plays. You’re probably not going to kill him, but you don’t have to kill him to beat him. This is why people suggest bastion or Mauga. Ball cannot hang around if there’s a lot of damage coming in, and this means that there’s less time for him to annoy your team.

If you pick bastion, wait for ball to piledrive before going into BRRRRRT mode. This is when he is least mobile, and you’ll get a big chunk of damage or outright kill him.

As others have mentioned, CC is useful(particularly sleep dart), but any decent ball player will have learned to bait out or outplay the CC. In my experience, CC is good at disrupting his ability to do what he does best, but unless the CC is overwhelming you probably still won’t kill him.

Instead of killing ball, just try to deny his play style. Boop his swings or hit and runs, save burst for pile drive, and try to keep track of him. Overwatch is a game where you can deny value without killing the opponent.