I have never been able to sleep on a flight

I have a long haul redeye flight to japan coming up (10hrs) and I have never been able to sleep sitting up, EVER. In the past ive been lucky with finding an empty row to lie down in, but this flight is fully booked and i’m stressed 😩.

Please do not suggest melatonin or benadryl, they don’t work for me! Im debating asking my doctor to prescribe me ambien, but looking for anything else similar that’s helped you!

for reference, in the past i’ve tried a foot hammock, countless neck pillows, melatonin, benadryl, sleep water, eye masks, earplugs etc and NOTHING works, my body simply wont sleep sitting up, on planes or in a car or anywhere and i NEED HELP!!! please