Sample size of 1.
A disc herniation caused me pain all night until it eventually destroyed my circadian rhythm. Even after it healed and the pain went away I had terrible sleep disruption. Up every 90 minutes, couldn't fall asleep until 4 am, waking up at 4 am. The works. Going on a few months.
Then I found sleep restriction.
First two weeks were brutal, but then biology takes over. And just like that, in a couple weeks, you rebuild you ability to fall asleep naturally and you're back to normal.
And in retrospect, this is exactly the approach we took to sleep training our young children. I swear by it.