Babies arms too active

My 8 weeks old has always had very active arms, even in the womb she’d move them around her face a lot so we never saw her face up until she was born. That’s becoming a problem now, as whenever she falls asleep and is placed in her bassinet she’ll start moving her arms rapidly in her sleep and hit her face repeatedly which of course wakes her up. She doesn’t want to fall asleep swaddled and will sleep only in a sleep sack with the arms out. I’m not sure what to do. She’s otherwise a good night sleeper but those arms are preventing her from sleeping well. This doesn’t happen when she’s in my arms tho. Don’t know what to do