2 year old awake for 3+ hours a night

So my daughter has never been a good sleeper, but before she would wake up 1-4 times a night and you could put her back to sleep within 10-15 min span. Now, it’s turned into hours and hours. I was wondering if anyone has any advice ??

She does have sensory (we are waiting for an assessment date) and doesn’t speak so we are unsure what could be troubling her and she can’t settle herself so cry it out doesn’t work for us. Currently, she has had the same bedtime routine since she was 6 months old, has a 2 hr nap during the day and 1 hr of screen time (tv) a day but it’s spilt up. She has a sound machine and night light.