I went from the factory 215/65/15’s to 255/50-16’s and the ride got stiffer the same as you’ve noticed.
I believe the factory tires were only S rated and have a softer sidewall than V rated tires.
I didn’t notice any difference in ride when going from 16” wheels to 17” wheels.
I ran 255/40-17’s fronts and 285/40-17’s rears. The sidewall stiffness is similar between 16’s and 17’s, the ride difference is negligible.