The Tires are too NARROW ~ Resulting in a less than desirable feeling of sure-footedness.
My '16 with the 19" OEM Split 5 Spoke came with OEM Bridgestone Turanza EL P245 / 45 / 19 tires.
Road grooves and surface imperfections seem to just swallow up the narrow tires and send feed back to steering wheel.
With just 13,000 miles on the car and original tires, I can wait to to get wider tires when replacement time comes.
That will be my route to attempt to improve the ride quality and gain a sense of better handling.
Nothing like a Pandemic to keep me working from home and away from putting on fun commuting miles on the QX50 . . .
Agreed, the Factory 18" wheel looks old and tired as it's been around since '07, the 19" looks a bit better, but still lacks a " Beefy " appearance.
Check out some wheels from other Infiniti or Nissan Models
Believe it or not, some newer Murano Designs would look good on your '16 QX50