When you say 'stiff' are you referring to hard suspension bouncing you around or resistance in turning the wheel?
If it is the latter, that could be an indication of under-inflated tyres.
At the recommendation of the tyre supplier, I run mine at 41 psi, and steering is noticeably lighter.
NB. They made this recommendation when I replaced the first set of tyres, they showed me that the old tyres had significant wear indicating under inflation. They confirmed this by putting the car on their scales and checking the tyre manufacturer's recommendations.
I came from a sports-car background, and was relieved that the PHEV suspension was so 'soft' by comparison.
But, if you're coming the other way, from a saloon style car, I could see the PHEV suspension seeming very hard.