Eliminate the left light. That's more light than you need and it's throwing everything out of whack. Keep the large mirror because the lights fit it. Replace the smaller mirror with a decorative mirror in a shape other than rectangular. You'll still have enough light at that mirror for most tasks. A wall-mounted and hard-wired lighted make-up mirror would be nice but that involves an electrician.

What if you get three smaller mirrors instead of two? Center two mirrors under the light fixture on the right side, and one on the left? Another option would be keeping the mirrors and adding decorative molding.

I would suggest recessed lighting and remove the decorative fixtures, but that may leave too much space between the mirror and the ceiling because of the mirror height. You could just keep the mirrors or frame them and replace the light fixtures with a tubular light version. I think your current light fixtures look too heavy.

Here's a window over a vanity. The oval gives you a different shape than the window and the large rectangular mirror. You can treat that vanity as a separate make-up area where the mirror doesn't have to match, just has to complement the other mirror. You want to center it over the sink however. It's hard to see how much room you have on that wall.

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Too bad you can't lose the left sink, drop the left mirror and make a small storage tower alongside the window on that area of vanity. Well, absent that...

The mirrored door medicine cabinet is throwing a lot off, if you are not using that, could you pull it and go to simple wall? Perhaps drop the left light and put in an oval, framed mirror centered as best possible on the sink. For future, lose the lower cabinet and sink and change that to a makeup area? Its positioning and spacing make it a pretty useless sink.