A thin frame is going to look anemic in here. All of the lines are so delicate and you need something to stand out. I'd consider a mirror that has a little more going on. Look for wall mirrors, not just bathroom mirrors.

Don't know that this is the right mirror for your space, but just to introduce you to the idea of a mirror with just a little more going on.

Have you selected new towel holders yet?

Interesting! Love the feedback! Thanks!

A longish oval may soften and sit nicely among all the geometric lines on wall and floors

Since the space is small it might be good to keep all metals the same as well…

When I had my upstair bathrooms renovated, I chose Minka Lavery pivot mirrors. They are well made and are a classic look. They come in all shapes and sizes: oval, square, round, and rectangular. They come in several finishes. My husband is very handy and he expertly installed them. The installation was a bit tricky. Best of luck on your journey!