Then one day I moved to a house that had no internet, and we would have to wait a month to have satellite put in, and we had no smartphones
After 20+ years of just thinking I had a sleeping disorder, losing internet access and living like a pilgrim caused my sleep schedule to naturally coincide with the setting and rising of the sun
Without any deliberate effort from myself whatsoever, I would get sleepy at like 9pm, and wake up around sunrise, wide-eyed and ready to start the day
I thought I had tried everything too, including screen limitations and so on. That probably didn’t work because just the awareness that I could go online if I wanted was enough to keep me awake, feeling like there was a party going on that I wasn’t there for. And of course I would cheat some days, and doing that even occasionally was enough to reset my progress to zero.
There’s probably some kind of “disconnection retreat” nearby you could try, where people get together in some remote place and stay off tech for 7+ days. Could be a fun way to see if this is the cause of your sleep issues.