You accomplish the desired look by purchasing standard 24" Vanity Base and two 24" Drawer base cabinets from a local dealer that carries in stock cabinets. What city are you in. We maybe able to help you guide you to a source that can help you. Get these vanities and have a local granite/quartz fabricator make a top for it with the cutout and sink. You can have a fully semi-custom vanity in about 7-10 day turn around. The beautify of going this route, gives you the option to choose from different colors that can coordinate well with your other selections.

have you thought of a wall mounted sink? They come like this with a vanity attached. you can put legs under it if you want or just have it wall mounted. Home Depot has stock like the last photo But it includes real Stone vanity and an undermount sink. There are tons of options/ sizes.

for storage, you could Mount two sinks and put a cabinet in between the two sinks, like this photo. Or you can put two sinks next to each other and add either a built-in or a wall-mounted medicine cabinet -- I love the big ones with the extra shelf underneath like this one.

Home Depot and money online vendors have every type of stock cabinets in the bathroom Department. another one of my favorites is the hanging mirror (over your closet door) with storage behind it for all of your jewelry, etc.

here it is, first photo is a marble-top vanity in stock at Home Depot. you can purchase a single or double sink with vanity included and haven't wall mounted. some have integrated storage. you don't have to fill the entire horizontal space of your vanity area. You can Style underneath baskets for towels, etc.

Two sinks are really going to mess up storage in the vanity. Another bowl and all those water and drain lines.

I am totally confused, there are tons of 72” vanities with 2 sinks you will need some plumbing work to do this .Go to Wayfsir they have many.To be honest I would rather have the counter space than 2 sinks but that is me.

A local cabinet store with RTA assembled cabinets. Their prices can be quite competitive compared to Lowes or Home Depot.

Get the built in look by getting a filler, sink base, drawers, sink base, filler.

If you don't have a lot of storage then filler/drawers/1 sink base/drawrs/filler.

With your vanity being in an alcove, be aware that neither user will be comfortable at the sink if you use 24" sink bases. Go for a larger sink base so your elbows aren't bumping into the walls. You could do 30" sink bases and still have 12" for your drawers. That will also allow you to use three sconces if you wish.

Online vanities seldom optimize drawer storage. It's sacrificed for some type of decorative element. You want a standard wall-to-wall sink base/drawer base/sink base with a filler strip on both ends. That means no fancy legs and fluting. Pretty it up with a nice door style and add feet in the corners.

You want the drawers to go to the counter, not to a decorative panel where you have to reach down for the top drawer. Frameless construction will give you more drawer space than framed.

https://www.masterbrand.com/get-started/design-your-room/cabinet-construction/frameless-cabinets

I am doing a semi-custom Omega vanity and I was quoted six weeks. Omega
is part of Masterbrand, with plants throughout the mid-west.

Ready-made vanities are not typically meant to go in between two walls. You’ll have to be mindful of the design of the vanity to make sure it will fit without narrow gaps between vanity and wall. The countertop that typically comes with these vanities will most definitely not work. You can get a custom or semi-custom vanity in 4-6 weeks.

Ready-made vanities usually have gaps on sides.

To get the built in vanity look semi-custom vanity cabinets or custom vanity with fillers on sides.

Some pre- made can get fillers to match.

Be aware a lot of pre -made vanities are made of cheaper material. Find out what the material is before buying. If materials are not shown or vague, it's not a good sign.