If it were me I’d put in a full length mirror (ceiling to walls to counter) and 2 or 3 lights in the mirror. Or do a nice LED one (especially if you’re into makeup). You have the perfect situation for the full mirror, obviously it would have to be custom, but it would open up the bathroom tremendously.

I agree with KR - the spacing will be the issue with 2 mirrors and sconces and not lining up over sink/ vanity area.

I have a sink and lowered vanity area in my master bath.

I have a custom mirror treatment with wall to wall mirror and then decorative mirrors which demarcate the sink versus seated vanity area. The sink has two vintage sconces which are for styling and the seated vanity area has a lit "Hollywood style" lighting arrangement.

I have a small master bath (urban high rise) and the mirrors certainly do increase the feel of space and light.

Here's a picture when I was moving in

One issue with getting one large round mirror is that the lowest point of the mirror will be at the center of your vanity. So if you're using the make-up area to put on make-up, it might be harder to see an adequate reflection because you are on the very bottom left corner of the round mirror.

Like K R suggested, you could go with LED mirrors. One large mirror or you could even get 2 slimmer LED mirrors.

Or here are some other examples of using smaller mirrors for each section: