I'm sorry, I linked the wrong dang one. It's this one. Trust me. This is something you can do. Just go really slow with light pressure. A very little bit at the time and check between cuts. Don't cut very long at all. All you're looking for is a clean, unifom seat. You're not trying to enlarge anything.
https://www.homedepot.com/p/Drill-A...-Bit-with-Single-Flute-DEWSFC5-8-60/310465672