The M1 used in the original MacBook Air has a TDP of around 10 watts. I don't track this closely, but AFAIK there aren't any good performing chips on the PC side of the world that can beat that.
I don't really track this directly, but periodically I look for passively cooled (fanless) laptops. I haven't looked into Ryzen, but it would be a very nice surprise if there are fanless Ryzen laptops out there.