#1- why "gasoline only"? SWMBO hates all diesel smell - and she's the main operator.
#2- why 2wd with a locking diff, presumably ruling out a 4wd unit? Because the L120 will climb the areas we want to use it on - barely - with her on it. It runs out of transmission - K46, old and tired. Worse once warmed up. Useless with me on it on a grade. I have a 34hp 4x4 CUT for the really tough stuff.
#3- have you ever tried a front mount mower? No.
#4- how many acres will you be maintaining with this mower? 1-1.5, mostly in spots too tight for my tractor.
#5- how long does it currently take you to mow? Several hours with a weedeater.
#5- are you absolutely set on buying new?... why? (?warranty?) All I see on the used market is crapped-out box-store MTDs and Ag tractors. Same reason I went new on my Kioti.
#1- gotcha... I know what it means to buy a lawnmower that's compatible with your dishwasher
#2, #3, and #4... the reason I asked, for the same amount of cash you're talking about spending on a consumer grade mower, you could buy a really nice commercial mower with a front mounted deck. You might not think it makes a huge difference, but it does. I was in your same position last year. I nearly dropped the cash on another JD, until I saw the new Husky R322 like this one:
TractorHouse.com | 212 HUSQVARNA R322T For Sale
...and just before I dropped the hammer on that one, I started researching commercial front mounted mowers, which lead me to purchase a used Toro 325 with a 72" mulching deck, 4wd, rear steer, hydraulic deck lift, adjustable casters on the deck (takes me three minutes to re-level the floating height of my deck), true hydraulic power steering (not "power assist"), and a partridge in a pear tree... all for less than half the cost of the Husky YT48DXLS you were looking at. It still has plenty of hours left in it, and parts are cheap. I went from the John Deere D140 taking 3-1/2hrs to mow, to less than 1-1/2hrs and DRASTICALLY cut down on trimming time. (FYI- all but 5 of my 26 acres is significantly sloped)
#5- yeah... hard to find a 48" cut string trimmer

#6- if you would be interested in buying a used commercial unit that will likely serve you much longer and better, I would highly recommend a front mount. They're out there for good prices... even better for you, the gas models typically cost less and are plentiful. Aside from the New Holland "MC" series... I don't know if any of the gas models have a locking diff. Good news is, you won't need it. With a front mount, the weight is biased/balanced over the drive tires... you sit on top of the axle, the deck is out front, and the engine is in the rear.
Now, here comes those dreaded letters... ZTR.
I, much like you, didn't even consider a zero turn, ESPECIALLY knowing how much they typically suck on slopes and are dangerous..... but you may want take another look. Not all ZTRs are created equal. There are front mount ZTRs as well... most notably, the Grasshopper 700 and 900 series. With a set of Carlisle chevron tread tires, these things absolutely DOMINATE when it comes to mowing... slopes or otherwise. I went and demo'd a 700 series a few weeks ago.... it WILL be my next mower, no ifs/ands/buts about it. (FYI- I hated ZTRs before I tried it). If you're worried about parts or service, Grasshopper leads all other brands when it comes to customer service and support. They're big on creating a legacy, so they support their older units far better than other manufacturers. Also, Grasshopper is a dedicated mowers-only manufacturer. They're also built extremely well. I can't tell you how many 700 series mowers I've seen with well over 6,000hrs on them. You also have a semi-local sales/service location in northern Bakersfield, just south of Oildale... Kern River Power Equipment. I'm not sure about your dishwasher, but mine loved the ZTR, and took a liking to the lapbar controls very quickly.
As for the "tight areas" that aren't practical for your CUT... there's nothing better than the maneuverability and accessibility you get with a front mount ZTR... but if you don't like ZTRs, then a front-mount/rear-steer is the next best thing.