I’m 6’4”, and my girl is 5’11”.

She likes the idea of getting a bike to ride through Miami Beach traffic.

(Part of me thinks a couple of Vespas makes more sense, but as she doesn’t drive, I’m pretty sure she intends to be a passenger.)

As I’m not an a-hole, or at least try not to be, I have no desire for a “loud” bike.

BMW GS Adventure. Great two up bike with great ergonomics for a couple of your stature.

You could try an Indian.
They have 2 different models that are great for 2up.

The Roadmaster.

The Pursuit.

I picked up a Roadmaster about 3 months ago and am having a blast on it.
I even road it from here (NC) down to the FL keys and back.

Note: I see you're in Miami.
Don't go to the Miami Indian dealership.
I stopped in there on my trip and it was a ghost town.
No bikes.. no staff... no customers...
You probably wanna hit the Ft Lauderdale one instead.

Head up to Rick Case:

https://powersports.honda.com/...cycle/scooter/adv160

When you sit in your natural relaxed seating position on a touring motorcycle equipped with a windshield, you want your line of sight to be just over the top of the windshield.
I have a riding buddy that is your height that has one of the big Yamaha v-twin cruisers.
I don't know if it's a case of him being "cheap" or if there just isn't a "tall" windshield available for his Yamaha.
Whenever we go on a ride and we invariably end up trying to ride an excessive amount of mileage in the available time, he whines.
Sometimes you just need to get out on the interstate and make up some time.
When we get out on the interstate above about 60 mph, he has excessive motorcycle helmet height above the windshield line of sight and experiences severe wind buffeting.
We have arrived home late, and late to destinations because he insisted on riding the time consuming back roads instead of the interstate due to the wind buffeting.

My Harley Road King bike & windshield fits me perfectly for my height and I have comfortably cruised at 85 mph out on the interstate without any wind buffeting.
About the only difference on my Road King cruising at 65 mph vs 85 to 90 mph is how often you will need fuel stops.

Windshield fitment for YOU is very important for riding comfort.

Powers77 hit it on the first try.

BMW GS.

Really, try one. Very comfortable bike.

Mine is an ‘03. Low miles. Old enough to be easy to work on it myself. 1150cc, plenty of power for 2 people. Smooth running. I paid around $3,500 for it in 2019. I think it has less than 20k miles (memory is going and I have 5 bikes). I am 6’ and the bike is close to being a bit tall, bit it’s still a great bike.

Might also try a R___RT if the GS isn't your style, bit more touring style vs the off road GS
There's also the K16 in the BMW line. I'm 6'0" & 34in inseam & the K is a big bike [in the showroom] for me.

Yamaha Tenere 700 or Yamaha Super Tenere or Honda Africa Twin may also be something to look into.

All fall under adventure rider motorcycles and are natural for tall riders (I have a Super Tenere). There are a few other models between Yamaha, Honda, and BMW that would also fit the bill that are more street oriented with sporty motors that Im forgetting. Suzuki, Kawasaki, Husqvarna, Triumph KTM, and even Harley Davidson have a few flavors to consider. Not sure if Indian or Victory have anything to consider. There are also several Italian brands that im forgetting.

I would not rule out sitting on / checking out other sporty ‘naked’ style bikes/cruisers that carch your eyes - especially v-twin or triples. These have the benefit of being sporty and light - great for commuting. Bit so are any of the other models above.

A large part of things is just what dealerships are in your area. Easier to have a bike you can get serviced locally - even better if you have multiple options incase one sucks.