@maxinvasion Hey, I found great practical solutions to a very similar problem in the book "The no cry sleep solution for toddlers".
It's well worth a read for anyone facing sleep problems with their kids. There's also a copy for younger children but our little one was early school age at the time, it made sense.
In our case, the solution we hadn't thought of was making a bed/nest for our then 4 year old in our room... so that when she woke she could wonder in, snuggle up and drift back off. Once that started happening we all got tonnes more sleep and life was much more bearable.
We now know the likely reason behind her waking up and being able to stay awake (seemingly stubbornly) at 4am was that she's autistic. We adapted our lives, moved, and now she sleeps in eyesight of our bed, she stays in it all night and has comfort that she can see us.
I strongly suggest the book, it had a tonne of practical ideas, grouped by the issue you're trying to solve, tried and tested by other parents going through it.
You do not have to read it cover to cover to identify the issue you're facing, read about the potential causes and practical solutions.
The thing I liked the most was they were practical, we put it into effect and almost immediately there was a tonne of relief.
Best of luck!
Oh, ps; your little one's problem sounds very similar to ours, maybe bed/nest is your solution too.