Hole Dozer Issue

Hey All, I finally got to bust out my hole dozer kit, using my m18 hammer drill. I had to cut out a 32mm hole on my sink to install an air gap.

I went through 2x hole dozers just to cut this small piece of stainless steel out. I'm assuming it was my technique.

I had my drill on speed setting one, and the clutch on 14 or so. I'm really frustrated it took so much time and energy jusy to cut out this little coin of metal.

And advice or tips would be much appreciated!