I will try to be as short as possible.

I had this situation where I would struggle to fall asleep, then fall asleep after like 40 mins just to wake up 15 mins later with a feeling that I can run a marathon. Constant fear of checking time and realizing that I barely slept would add to the experience.

7 years ago I had this job where it is pretty loud all the time. Loud as in static white noise from compressed air. 8 hours in a row, non-stop. After I have left the job and moved to another country, I have found out that extensive exposure to a constant noise levels above 45+db (I do not remember exact numbers, but it was around 45db) would raise anxiety in humans. Turns out that was it. But the damage was done and I couldn't sleep even after leaving this job.

I am trying to find an article from WHO about noise influence on the human body that I read 6 years ago. Only found this.

During my study I did fall asleep with phone playing some long and boring things. But then I got my girlfriend, and when she would be at my place, I did not play anything on my phone falling asleep. I did notice that if the thing is at bare minimum requires some attention, it would keep me awake for longer. So I have stopped doing this even when she was not around. It had an effect and I began to fall asleep naturally, albeit not in an instant.

My girlfriend also complained that she has troubles falling asleep. She did use melatonin pills and melatonin spray when we met. But since she also would not use phone in bed, she quickly began to fall asleep in under 5 minutes. When she was at her place, she would scroll insta and tiktok and would not get a good night sleep. So I began tell her to drop her phone before bed. Now since we are married, she does not scroll though the night and falls asleep much faster than me.

Today I sleep way better. I do most of the things I have mentioned in my comment. No coffee, no scrolling, reduced blue light on PC and phone, no bright light from ceiling lamps, more water during the day, seeing sun set. The only thing I am struggling with is food before bed. But it is night and day to how my sleep used to be.

Sidenote: maybe, instead of an engaging content, streams or any video where human voice is audible, smooth jazz, lo-fi or a rain noise track would work better. Basically, you need your brain to wind down naturally. It won't happen if it would keep accepting information from sound and/or screen