It sounds like you have provided lots of entertainment.
. Some things that might occupy him for a short time. Toilet paper tubes or paper towel tubes taped close on either end with a treat inside. A box of tissues or a roll of toilet paper. Bird toys that you can hide a treat in and he has to work to get it out. A container of safe dirt.
These are temporary fixes, I know. The only thing I can think off to discourage him from chewing on the bars that wouldn’t harm him is to spray a product called Yuck! on a cloth and wipe the bars with the cloth. It is very bitter tasting, but made for animals so it’s safe. Some other flavors I have heard squirrels don’t like are peppermint, cinnamon and eucalyptus.
Maybe someone else who has experienced this will offer a suggestion. I hope you can get him to stop. Bar chewing is harmful to his teeth.