Desperate for advice

I’m really struggling with my 16 month old son going to bed at night. We have been on a consistent bedtime routine for about two weeks now and it’s not helping at all. Maybe I just have to wait longer? But I’ve been trying to get him to sleep since 8:30 (it is now after 11) and he is still fighting me. Diaper is changed, belly is full, he had a nice long bath with lavender soap and then lotion. I have a lavender diffuser and a fan for white noise going on in the room.. he has never been a good sleeping which is why we started a strict routine. He takes his naps perfectly fine for me, it’s literally just at night. I need help 😣 sometimes after an hour of fighting I have to leave the room so I don’t yell at him. Of course he’ll just climb right out and come find me. I don’t ever want to do CIO but people are saying it sounds like that might be the only way.. please I need other options!! TIA