I don't have the radiator on in my bedroom ever. But I do have two proper, heavy, wool blankets which I can add to my bedding to keep me warm, as needed. I bought them about 8 years ago, new, and as I expected, they cost quite a lot, but they have been worth it. I knew they would be, as no-one even knew what a duvet was when I was little, although we did have eiderdowns. And can you believe we had coal fires in London up to about 1963 - most people did.
My bedding these days normally consists of a duvet, with my weighted blanket on top. In the coldest parts of Winter, I take a hot water bottle to bed, and add blankets as required.
If it is really cold, adding an underblanket, under the bottom sheet, can also make quite a difference - it stops the cold striking you from below the bed.
If you read up about how to get good sleep, a cool bedroom is recommended.
@RafaistheKingofClay
obviously you don't live where I do, I suspect you may be further North (I am in NE England). Just saying what I do, not criticising 