Transition to crib - tips?

My 11-wk old has never been able to sleep at night in his crib or flat surface (not an exaggeration). We have a bedtime routine that works well for his current sleeping location (pediatrician-approved rocker), and use a swaddle and white noise machine overnight. He is outgrowing the rocker but can’t stay asleep longer than 15 minutes when placed in crib. I place him in his crib asleep after nursing. He grunts, rocks himself around, and eventually wakes up - just like he did at week 1. I then will try shushing and giving a paci to sooth to sleep (this is our nap routine). That doesn’t work either.

He does short naps (30-45 mins) in the crib during the day. He can put himself to sleep for naps.

My firstborn used the same rocker, and while he transitioned out much later, would periodically sleep on a crib or flat surface overnight. So I’m at a loss - and though this sounds crazy I feel like I must have the only baby in the world with this weird quirk. He won’t be sleeping in a rocker at five years old, but I’m halfway convinced that he’ll never sleep at all. Any advice out there?