Does he still nap? It might be time to drop it so he is tired earlier. Also, I think a walk or some time outside around sunset helps and dimming the lights around the house as you're getting him ready for bed. Make sure he's eating throughout the day, not so hungry that he eats a giant dinner and has a big load of calories to burn off. Remind him he needs to go back to sleep if he wakes up at night. Also, ask if he's too cold at night. He might need an extra blankie for winter.
Our little one has a hard time going to sleep during the night, but I noticed if she walks up and down the block with me it tires her out. Usually around 5 is our ideal time so it isn't too dark. I've been putting YouTube on with the dark screen and calming music too, which lulls her to sleep.
Find something he likes a lot and use it as a way to start the process. My son loves blaze and the monster machines so at bedtime I tell him he has to lay down and he can watch blaze for a little while so he does and goes to sleep. My son use to fight going to lay down at night but when he knows it’s close to bedtime he grabs my hand and wants to go settle down and watch his trucks for a little while before going to sleep.
no advice but my daughter has been doing the same thing. getting up and coming into our room 5 times a night 😭
Some things that helps us are - bedtime routine - no screens before bed - snack before bed (make sure he's not hungry) I also keep reminding to close his eyes while trying to fall asleep and that helps too 😊