Hi, mamas! Sleep related question - looking for advice or suggestions!

My husband and I started a sleeping “routine” for our little guy since he was about 5 weeks old. He gets his bath (when it’s bath night - and his bath totally chills him out. He loves it and is relaxed when he’s done), we read a book, and then I’ll nurse him and rock him to sleep. He sleeps in our room in the rock and play sleeper (as per our pediatrician due to severe reflux) - I first put him down between 9:30-10:30. He will always sleep for at least three hours, no problem. However, every time after that that I try to put him down, he will not sleep in the rock and play for more than 30 minutes. He will wake up, nurse for five minutes, and then go back to bed (which makes me think that he’s not waking because he’s hungry).

This has been going on for at least a month and I’ve been trying to adjust/rule out things but I’m at a loss 🤷🏻‍♀️ I’ve tried putting him down after he’s totally asleep, I’ve tried putting him down when he’s falling asleep so he can fall asleep in his own. I’ve tried swaddling, not swaddling, arms-up swaddling - pacifier/no pacifier - leaving his hands out to self soothe, etc.

Am I missing anything? Or just ride it out because he’s still little?

Thanks!