Newborn more comfortable sleeping in just a diaper?

Anyone else going through this? Babe is 3 weeks old and if I put him in a onesie or swaddle him he wakes up during his sleep almost every single time and fusses. After his usual 5 am feeding I remove his clothing and put a LIGHT folded muslin blanket wrapped around his lower body only plus a hat and he sleeps like an angel (and sleeps much more comfortably it seems). I typically put a heater(not VERY hot) on to keep the room warmer when he sleeps.. curious to know if anyone else's little one likes this as well..