Hi,
Here are some temperatures logged in my attic for quite a few months for whatever its worth:
https://www.builditsolar.com/Experim...AtticTemps.htm
Note the large daily swings -- I wonder if you are weighing the daytime period with solar heating too much? Nights are long in the winter.
I'm located in SW Montana.
You can blow in cellulose with a blower that Home Depot will loan you for nothing as long as you buy the insulation there -- cost is very low.
Gary