Hi, it sounds like you're dealing with some pretty tough driving on your new Z254F right? good Apart from lowering the tire pressure, something you can try is (check the seat suspension) Some models have the option of adjusting the seat or even installing a suspension kit for greater comfort. You can also consider changing the tires for softer or larger ones, if compatible with your model.
Another trick is to make sure the ground is as level as possible, as uneven surfaces can make the machine feel stiffer when driving. If anyone else has had this problem and resolved it, it would be good to hear their recommendations. I hope you find the solution