You could also ask the better question on what is your current driving habits? I will assume that you don't just own a car to drive to and from work and the rest of the time the car is still idle on the driveway.
When I got myNiro, there wasn't any plug in option at all. I would hazard to guess that it still isn't really an option here in Ontario as the government cancelled the rebate and most of the manufacturers re-allocated the plugin stock to locations that do. I don't know if a PlugIn hybrid is easy to pick up where you live. But I bring this up as I don't drive an awful lot but sadly it seems to be the worst type of driving around. Quite a bit of short distance trips rather than ones of substantial length or distance. Like, grocery shopping is 2km away. Far to far to want to walk with a whole load of bags. No direct bus route, so you drive. Dance classes for kids, again, can't expect them to walk as it's a bit too far, but not far enough to give the car chance to warm up. With my old gas car I got the same horrible mileage like you get in the truck because the engine never got a chance to warm up and was always running in stop and go traffic lights.
I know I would be perfect candidate for a PlugIn. I did get the 2018 hybrid and have seen a significant saving in the cost of fuel even considering my driving habits. The stop/start I can get savings by accelerating a bit slower and letting the battery/electric motor do more of the work. If your vehicle does lots of the stop/start short trips during the not to work time, then it would be a great option.
But consider as well. You get far more colder and longer winter than most on this forum. Over the cold times if you want to have heat, then your engine will be running. I found when we had the -20 cold snap, and I did take some longer runs. Even though my engine temp was a good 3-4 bars, and nice warm air was coming out the vents, the car battery was at 80% full, yet the car decided that the engine needed to be running full time. Its because the temp of the air coming in was cold enough that the sensors determined the engine needs to run. Sure, in the warmer times you will get a better economy if you can charge and drive full time on battery, but you must realize that isn't going to be all times all year long. The cost of the PHEV is more than the HEV and you might need to do the math to figure out if your break-even makes sense. No point paying the extra for the PHEV if given your driving needs it will take you 5-6 years to recoup the extra cash to buy over just getting an HEV model.
I sympathize with your situation and I can relate to it.
It wasn't that long ago that I was living in Maine and had a similar driving regimen. I work from home so I don't have a daily commute, but I tend to make lots of short trips around town. When I lived in Maine, my Toyota pickup was usually just barely beginning to throw some heat on the coldest winter days when I would arrive at my local grocery store and shut the engine off. If I was doing that same drive with my PHEV Niro today, I think psychologically I might be irked by the desire to make the whole drive in EV mode, and not have any cabin heat, but realistically, it would have worked out about the same in terms of comfort, because the truck never got warm either. I haven't tried this with the Niro in a truly cold climate, but my impression is that my Niro starts throwing at least a tiny bit of heat sooner than my old Toyota pickup would under the same conditions. Neither one would throw a useful amount of heat on a two or three mile trip to the grocery store in 10 degrees F weather though.
In terms of fuel economy, my PHEV is great for my kind of driving. I take it out several times a week. I last filled the tank on Jan 2, and the tank is still reading full. Almost all of my miles since Jan 2 have been all-electric. But I'm in Southern California, and it's easier to run around without heat here than it is where I used to live in Maine or where you live.
The PHEV also has some small advantages over the HEV in terms of driving in heavy traffic congestion, and at times when you need more power than the ICE can deliver (long mountain climbs). But as you point out, it is pricey compared to the HEV. And if you are in this solely for the economic considerations, then there are probably a lot of situations where the HEV is the better choice.
On a slightly tangential note: when I'm driving in EV mode, and deliberately refraining from engaging the ICE, the car feels kind of lethargic and lumbering (if I recall, we've only got about 40 HP in EV mode). But it's still peppy enough that I can still take off from a red light on just EV power and accelerate faster than maybe 80% of the other cars stopped at that same light, most of the time. But a few months ago I found myself in an awkward situation: I was first in line at a red light, but there were a lot of cars lined up behind me and I needed to move over one lane when the light turned green, and I only had about 50 yards to do that in or I would miss my turn. So I kicked the car into sport mode, the ICE started, and about two seconds later the light turned green. I hit the accelerator a little harder than I normally do, because I wanted to get out in front of the car next to me in order to have room to change lanes. But I was accelerating based on my experience with EV mode, not Sport mode, and I was astonished to experience my humble little Niro not just "squawking the tires" but literally "burning rubber" as if it was some kind of muscle car. Wasn't intentional, and it's not my usual way of driving, but after I got over the brief period of shock and surprise, it made me smile just a little bit.