The tuck isn't the problem, it's a symptom.
I'd say 33% chance you're not getting enough height and rotation on takeoff, 33% chance you're not using visual cues while rotating, 33% chance it's both, and a 1% chance it's something else.
The specific fixes depend on which of the above it is, but no matter which it is, the first thing I'd have you do is work fulls on trampoline until they're perfect and consistent and you're seeing the landing for the entire skill and maintaining a perfectly straight body. From there, I'd have to be working with you in person to be sure.