I'm in the same boat. At 6'-3" been riding drop bars forever but getting older and just not using the drops, it is too uncomfortable to bend over that far.
I put flat bars and 28mm tires on my 20 year old Specialized Allez and I find it much more enjoyable to ride.

I just turned 74 so my birthday present is a Trek FX Sport 4 and I love it. Carbon frame, disc brakes, flat bars, 10 speed.
I upgraded to carbon fiber bars and seat post, changed to a 11-34 road cassette, 30mm tires, and put on some lightweight flat pedals.
For me it is the perfect gravel - road bike, lightweight, good seating position, fast.

It is not a real hi tech drop bar road killer, but it is light, fast, and very comfortable and affordable. Ten gears is all I need. Keep it simple.
They make the FX Sport in an XXL, that would probably be a good fit for you.