Hey. I'm not sure if I can be of much help to you, really, but I wanted to reassure you that, yes, I found sometimes it would take a long time to settle my baby when she was little. She wasn't all that consistent either.
The feed play sleep thing is a great guide, and that's the pattern we've mostly followed, but certainly there were times where it didn't work out like that, and once I grew comfortable with that it was ok. If you're breastfeeding, you could try giving a topup feed before putting him to bed, if you're comfortable with that. My DD fed to sleep sometimes when she was really overtired and it was a really useful tool to have up my sleeve!
HTH a little bit. You're doing marvellously