I would do one large framed mirror. Two individual mirrors look crammed into the corners. A single large mirror would look more intentional and well-proportioned to the space.

I would make a frameless mirror across the entire width of the wall - from corner to corner. At the bottom - to the edge, at the top - to the line where you marked the mirrors.

If you use the vanity to put on make-up or styling hair, having one mirror cover the span will be better accommodating so you're not stuck hovering over a sink.

You Buy a 66" x 32" framed mirror, paint the frame white, or a color, or black

Hang horizontally and D.O.N.E

( no to frameless! edge to edge.) Looks builder junk....unfinished unless framed on all sides by a contractor and then a template for glass )

Buy framed, you have to pick the lights already in place................above

Right here....36" x 66" and perfect size.

PAINT IT.!!

https://www.wayfair.com/Gracie-Oaks--Sailee-Rectangle-Full-Length-Mirror-Faux-Wood-Farmhouse-Mirror-Floor-Mirror-OPIY2393-L41-K~NOHX1282.html?channel=GooglePLA&ireid=185538293&fdid=1817&PiID%5B%5D=66917752&refid=GX712222951401-NOHX1282_66917752&device=c&ptid=2437885529231&network=g&targetid=pla-2437885529231&gad_source=1&gad_campaignid=15284866713&gclid=Cj0KCQjwoP_FBhDFARIsANPG24NoWEUCks9slRJ1v2oiV5-wF_r7vQRBC5Lpy0snB3UtGnQaJq6w8A8aAkR9EALw_wcB

A corner-to-corner mirror is like a wall finish and is attached accordingly - with full installation (like you would attach tiles, for example). A bevel along the edge is of course necessary. A mirror with a frame is a traditional option.

Just easier all around.............: )

No, that is not me: )

Don't do this below

I’d use two interesting rectangle mirrors for a lighter more contemporary feel.

This one comes in 3 sizes and if interested, tape out to get a better sense of the overall effect.

https://www.amazon.com/dp/B09JNNM5CR/?th=1&psc=1

Don’t buy lighting until after the mirrors are installed to be sure they work well together.

The dead wall..............serves NO purpose. The area is already wired for the lights. I call this CLUTTER me up!! Tooooo small : (

You get more light more sparkle with ONE mirror. Big