Yup I absolutely fall off a cliff if I'm consistently consuming a stimulant. That includes caffeine. It's actually a problem where I have to be careful that I'm not having it too early (as opposed to late) in the day otherwise it will wreak havoc on my life.

in my case I need to take it at a perfect time where it stops working just after I go to bed. Take it too early and it will stop working before I go to bed and I won't fall asleep because my mind will distract me from it. Take it too late and I technically will sleep, but I won't actually feel rested in the morning.

Nah, I'm taking a very minimal dose (adjusted) and I know that my sleep is less deep and shorter. Without medication I sleep around 8 hours, with 6:30-7 hours.

The best that helps sleep in my experience is doing sports. Lots of it.