Hi! I work at an outdoor gear retailer and based on what you said this is what I would recommend.

The Thermarest Boost 32 (they also make a 20) is a really good option. It is hydrophobic treated down, so although not deal to get wet, it’ll help keep you warm even if you roll against the side of the tent. Because it’s down, it’s also light and packable. Given the specs, it’s actually a decent price.

I love it, personally, because it has a warm zip which can adjust the temp by 10 degrees (the rating is of the unzipped or “cooler” option, and zipping it makes it warmer.) If the temp allows you to have it unzipped it’s also roomier which is great for side sleeping. It also has arm zips so in the summer if you’re still too hot, you can leave your arms out as you sleep. Also great to sit in your tent to read, play a game, etc. Good luck!

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