There’s a specialty bit available that sort of looks like a pineapple (or maybe a better description is what a differential pinion gear looks like, only smaller). I’ve never tried it, but the idea is you grind the end of the stud flat, then use that to make a bowl-shaped depression. Then when you start drilling, the bit naturally starts at the bottom of the bowl, which is the center of the stud. I’ve not been able to find a picture of what it looks like b/c I don’t know the name of that type of bit. I’ve seen it as part of bolt extractor sets in hardware stores.