I was once always cold, but that was only during my hypothyroid period. When I was hyperthyroid I could just walk with t-shirt and shorts in the winter becuase I felt so warm.
Myself use a thick duvet during winter, I always sleep with my window open because I’m allergic to my bunnies hay. I find it helps sleeping with socks, thick duvet and worse case I will put on more clothes and have a fleece blanket under the duvet.
But I also have quilt that warms up with electric, which I can use to warm up my duvet and put my cold limbs on. I later turn it off when the duvet get warm.
That’s the things I did to handle when I was freezing because of being hypothyroid.
My dad also got a small portable heater, which can work as an AC or heater. I will sometimes turn it on during winter and it will be warm and cozy.