I have a LR RWD from 2018, and I drove it last winter on winter tires. I would suggest you get a dedicated set of winter wheels and tires. Makes the switchover much easier and also keeps the summer rims in nice shape. Although the stock tires aren't bad, stopping and general traction is definitely improved with winter tires.
There is no problem at all with the RWD. The traction control is really good and you will find it really hard to get it to slip those rear tires out, and even if you do it is only slightly before it corrects. As you said the weight is a benefit.
The only thing to keep in mind is this is a fairly low car, and if you are going through a some really deep heavy snow you will not want to stop if at all possible. Light deep fresh snow is no problem. But if it is heavy packed snow and it is higher than the bottom of the car you have a huge flat surface under there to jam up the car (I find the snow plows tend to pile up snow ~2ft high at the ends of side streets around here, so I make sure not to stop on them). This is a problem with any car, of course, but the flat bottom makes it a little worse.
Once you have the car and get a nice snowfall take it to an open parking lot and get a feel for it, accelerate fast and try some turns at a good speed. it will surprise you how well it sticks and no fishtailing!