Key being the hills. The Kubota will not side hilling as well
You bring up a great point and genuine issue if one has hills, which i used to all my life but now live in an exceptionally flat area.
no zero turn does hills well and if one has ever done an out of control spin down a wet slope in a zero turn, please raise your hand...
The answer is out there but it's seriously expensive. Kubota's out front mower has been made a long time, my older brother in Virginia has one over twenty years old,
many thousands of hours on it, and what saves him is it is all wheel drive. It handles hills very well. They cost now about 23 grand, maybe a little more.
Like buying a small tractor. But the quality is similar and it seemingly runs almost forever. Amortizing the cost of an expensive mower over twenty years
of realistic use starts to make the difference in annual cost of operation. I'm a retired finance guy so I look at annual cost of lawn maintenance. Plus I'm a motorhead so the
performance and feel of the machine is important.
Alternatively, you can buy a Bad Boy at Tractor supply for five grand and likely wear it out in three years, and then perhaps if start up costs are no longer an issue, get the mower of your dreams. Mine was that Kubota, or the JD equivalent. For ten grand less than the dream Kubota I could get a diesel JD garden tractor that mows like a dream. Cheapest entry in diesel with a steering wheel.