3 month transition swaddles

My baby boy will be 3 months next week. We have the “love to dream” swaddles for night time that the hands are up by his head. Has to have a swaddle to sleep due to startle reflexes. With him starting to roll on his side what is the easy way to transition swaddles with arms out? Tried sleep sac with arms free and could not sleep, had to go back into swaddle. Any help!