PC tools aren’t what they used to be since bought out a few years ago and they may never have had good bearings ever. One of my sanders has a skateboard bearing in it. You may want to look at a different motor or go with a 7519 which I think was the single speed model at plus 3 hp. Less to go wrong. Then use a good remote speed controller.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.