Try the 478 breathing method when you’re ready to go to bed. This method was apparently developed by the military to help soldiers fall asleep “at any time.” Reduce all light exposure and put down your phone at least 1.5hrs before bed. Force yourself to just stay in bed with your eyes closed, no stimulation whatsoever. Breath-work will probably be your best bet. It takes time and practice but you will eventually improve its effectiveness the more you try it.
Btw, the nicotine in cigarettes and tobacco is actually a stimulant, like yeah it feels relaxing but it actually raises your heart rate and keeps you awake at night, so if you actually tried to quit smoking, after a while you might start getting better sleep.
Are you able to go for a long walk? That helps so much - light exercise to ease the body so that the mind follows as well. Please don’t smoke during a dry fast, that is severely dangerous and it isn’t worth being hospitalized for something that you know is dumb.
Unfortunately part of dry fasting is facing that insomnia as well. It’s an unpleasant side effect for many people. I do find that walks help a lot