We used Muslin more cause it’s thinner (but those swaddle with velcro/zipper is more convenient), but stopped after a few days cause my baby hates being wrapped. Maybe get 1 of each to try? Skip the 0-3, go straight for the 3-6 months onwards. I got my 0-3 all from hand me downs. I didn’t managed to wear most of the 0-3 within a month (my baby is on the smaller side btw). 😅
Get both muslin cloth and the Velcro swaddles as the latter one is convenient. I bought onesies for newborn size and 3+ months both, as babies grow out fast from the newborn size