I was going to say that is just how they behave on grades until I watched the video. That grade doesn't appear very steep.
I cut in the road on my new land last year, at the peak was 14% grade. I definitely was losing speed on that grade. Brought a case dozer out to cut to a more acceptable peak of about 8% at its worst transition. The dozer would track up it fine with zero hesitation. But my c238 still does not love the high grade with a full bucket. But the dozer and skid steer are nowhere near the same function.
Your machine and mine are about the same hours, I've got a little more. But your grade looks less. If I were you, start saving for parts and see what the flow rates are. Granted your machine is for making money, mine is for personal use. But 3000 hrs +, have to be realistic with expectations