A Ventrac would be an excellent machine. But expensive. An F is also expensive, but it'd crush your mowing. They're often available second hand, and they're a super durable machine, so could be good buying. The reality is that it's more machine than any residential owner needs, but still, you asked for us to spend your money.
Mowing steeps to my mind comes down to a few things:
1. If you can, mow straight up and down, with a runout area at the bottom. If you need to, modify your property to make that possible (take down trees, move fences). If that's possible, then most tractors will mow just about anything, it's really hard to tip a tractor over its tail if you're even moderately sensible.
2. Failing that, then on the steep side slopes, go slow. My B2601 is stable on a slope that I'm not comfortable on. When I get off and rock it, it's nowhere near tipping. But do that same thing at any speed, and one bump or put a wheel into a hole, you're gonna be on your side. Also, really important your loader is off - a loader puts a lot of weight up high. I have no ballast in the tires, but either ballasted tires or spacers make a big difference.
3. Some things just shouldn't be mowed. So don't mow them. Make a wild flower garden or let some trees grow. If it really has to be mowed and it's more than 25-30 degrees, then it's line trimmer time.
If you want a cab and to be comfortable, the L60 (Grand L) are the machines to have. They're also a bit more capable, and have a trick transmission that does some really cool things. Messicks have a good video on that transmission. The L6060 is a 60HP machine, it'd probably do everything you want and then some. It's not an MX or an M, but it's probably at the top end of what a small tractor can do. It also has a mid-PTO for a snowblower, I think you mentioned you wanted that.