hot end cooldown during print.

My ender 3 max neo’s hot end started cooling down during the print. it would hold enough heat to print a few layers fine, then it wouldn’t be able to push filament through the hot end. i tried replacing the thermoster, and fixed any issue’s with my slicer. i also tried flashing new firmware onto my printer but it is stuck on the loading screen. i tried flashing back to the old one but its still stuck on the loading screen.