Babies quite often have their preferences I think! We put ours in a Purflo this week and he didn’t enjoy it much, but the Tommee Tippee sleep sack helped him stay down for a bit longer than usual. It is quite trial and error. Personally for sleep at this age I’d only go with name brands that come with safe sleep guidelines for heat levels etc x
Large muslins are what we have found best swaddles with them being so thin they aren't too warm and you can get a tight wrap that doesn't unravel every time they move x
I've always been advised not to swaddle their arms as it stops the startle reflex which is evolutions way of preventing sids x
You can get swaddle blankets on SHEIN! X