If you don't mind the extra effort to use the cooled cameras you're probably better off staying with those. I enjoy my full spectrum D5600 and have no intention of going to a cooled camera, but my average winter and summer low's are 3 degrees and 6 degrees respectively lower than Tabulam. We get quite a few frosts as well.
On the other hand if you want the simplicity of a dslr the D5500 will still do well for much of the year, but it costs about $500 to pay Camera Clinic in Melbourne for the conversion. I did mine myself using the Lifepixel guide:
https://www.lifepixel.com/tutorials/...rsion-tutorial
The procedure is fairly simple on these cameras but the parts are tiny - a bright light and some magnifying glasses which fit onto your reading glasses are handy. I just removed the filter from the d5600 and didn't replace it with anything.