Does he like to be swaddled at all? We bought a ‘Copper Pearl’ swaddle that let us swaddle tight around our little guys arms and keep it loose around his legs. When we started using it we were able to start sleeping without holding him 💤
I cover a muslin with my breast milk and put it over the mattress like a bed sheet and my twins settle because it still smells like me. They won’t go down just on the normal sheets
I found that warming up the cot first helped and that a dummy has been a life saver, but I still have to be careful putting him down, making sure he's bum down first and not removing my hands until he's more settled (and then doingso very slowly). If doesn't really work in the day but I csn mostly get him down into the next-to-me at night now. Putting him down on his side and patting his back or bum for a while can help too. Good luck!