I’m pleased to hear that you have a good coating job. They certainly have been better this past decade. I presume you have silicone. I use a razor blade and push up towards the wall on recoated tubs. If your blade gets dirty so that it could scratch, then use another.
Getting this area clean and dry is the most important part of recaulking. It gets so hard to do that we tend to just want to cover up the old stuff. Clean and Dry.