Multiple wake ups a night

Hi everyone! My son (3.5 yr old) was always a great sleeper.. until about 2 months ago. Around 2 or 3 months ago he got on this kick that he was scared of the dark so he would come out of his room multiple times a night. It started with just wanting his bedroom light on, then it progressed to wanting the light of the nearest room on too, not wanting the door shut, etc.

we’ve done all of the things he’s asked to make his room more comfortable/less scary for him, but he’s still waking up every 1.5 hours or so and running into our room saying he’s scared. We redirect him back to his room and he’ll sleep for a bit longer, then he’s right back. By 4am, he’s just up for the day. He won’t nap anymore, so he’s awake from 4am-8pm. With all the wakings, he probably isn’t getting more than 4 or 5 hours of sleep a night.

We’re exhausted and desperate for a solution.