Echo Park 35°

I went rei big Agnes, but I also have 2 (20 year old) down bags that I put inside each other that can keep me just as warm and combined they are as small and light as big Agnes but with down moisture is the enemy and in winter there is plenty so there is that

The lack of filling on the one side in the bag you mentioned is because the side you lay on (against the sleeping pad) will be compressed so much as to be generally useless as insulation. Cotton is a bad idea for anything intended to maintain warmth. I like the suggestion of the quilt and sheet made earlier.

I’d highly recommend a Big Agnes Echo Park. The interior feels more like cotton. Not at all restrictive and super comfortable. It’s also budget friendly. For a backpacking option, I really like my Zenbivy. The design seems a little gimmicky, but it’s just as comfortable as my car camping setup and really light and packable. Not at all budget friendly.

Big Agnes echo park long/wide. I’m similar in size to you and love mine! If you can’t find one for a good price (they sell $200 new but I got mine $140 on sale) then go for a camping quilt or Coleman big and tall instead

I love my Echo Park, but it's heavy.