I’ve always ridden my ‘97 with a solo Mustang seat... showing the fender. When I traveled, I reinstalled the passenger seat and luggage rack. It doesn’t take 10 minutes to take it on or off. I used the rack for a T-bag.
My wife has never ridden with me... (they don’t call ‘em “The Great American Freedom Machine” for nothin’) !!
This year I fabricated a mounting bracket for an old style 3-channel luggage rack that fits behind the riders seat in place of the passenger seat... one screw attachment.

Yours is the same luggage rack I used with the passenger seat... it’s not quick detach, but not time consuming either.

You can add a quick detach hardware kit from HD, then a quick detach passenger backrest.

Quick detach the bags, Loosen the Phillips screws on the chrome strut covers, loosen the bolts on each leg of the rack using a box end wrench, then remove them using your fingers...( the rack has threaded bungs ) remove the license plate, two bolts that go through the license plate bracket. Then it slides out. It does take 10-15 minutes. You will then need a different license plate mount or the stock one.

I’m guessing the dealerships still sell the quick detach hardware kit and the quick detach backrest.

H-D Detachables Docking Hardware Kit

Part Number 53803-06

$44.95

Luggage Rack for H-D Detachables Passenger Sissy Bar Upright

Part Number 53011-98

$209.95

your backrest pad should fit.

I bet I’ve taken mine off and reinstalled it 50 times over the last 20 years... it becomes a one beer project!

Try google-ing HD detachables. They have a bunch of options for sissy bars in addition to the one I posted.
They also have a line called “hold fast” detachables... not sure of the difference except more options.