Looking for advice: we are moving away from the swaddle.

We have a baby that just hit 12-weeks over the weekend and we have begun to transition her from a swaddle to an arms-out sleep sack. Our LO isn't rolling over just yet, but she is outgrowing the swaddle (it's a wrap/zip swaddle.)

The speedbump we've hit is that she doesn't sleep as well unswaddled. In the swaddle, she will sleep for 5-7 hours straight before waking up for a smack. In the sleep sack she can only go 2-3 hours before she's waking up.

Parents, how did your transition out of swaddling go? Can you offer any advice on making the process smoother, or are we going back to semi-sleepless nights.

*P. S. We did get her a larger size of the zip up swaddle but it's too big and she can still move her arms around so it ends up being no different than the arms-out slepe sack.*