Match your fixtures with both the pulls and the mirror frame, or brushed stainless (which would be close enough).

Could you leave the fixtures and put a lighted anti fog mirror up?

If the pulls are already stainless, I would either keep the mirror slim black and repeat black in a couple of small accents, or go frameless and let the hardware stay the secondary metal. If you choose a lighted mirror, I would usually remove or soften the existing vanity lights rather than stack two strong front-facing light sources, because that can create glare and make the wall feel busy. For towels and mats, white, charcoal, or a warm greige usually keeps the mix looking intentional. I work with a lighting and metal hardware manufacturer, so I look at this from a production and QC perspective: the cleanest result usually comes from repeating each finish at least twice and keeping the vanity wall to two metal stories, not three.

Which pulls-knobs would you suggest?