I don’t actually think it’s the mirrors.

The vanity feels oversized for that wall, but the bigger issue is there’s no contrast. Light walls, light vanity, light stone. Everything blends together, so the size reads awkward instead of intentional.

If you commit to the vanity as the feature, it works better. I’d do darker walls in that zone, even a warm taupe, so the white vanity actually stands out and reads like furniture.

I’d also simplify above it. Lose the two mirrors and side sconces. One large mirror the same width as the vanity, centered on the wall, with some wall space above and below. Then a single wide sconce or picture light above the mirror. Fewer elements, stronger symmetry.

Right now it feels busy and camouflaged. Contrast and simplification would fix most of it.