Most hitters instantly think ‘MECHANICS!!’ when they’re struggling with pop-ups or foul balls. In fact, many times the players simply aren't giving their bat enough time/distance to travel UP the slope of the swoosh before contact.
Tee Work CAN Make this WORSE! Tee Placement Matters!
So, if you’re training by yourself, check on where you’re putting the tee when hitting off the tee. Are you hitting balls ‘too deep’ in your path and creating a contact point that’s on the bottom of the swoosh? If so, put the tee further out in front.
That’s part of the reason the Launch Angle Tee and Adapter are both angled forward. Don’t train yourself to feel ‘comfortable’ with a super deep contact point. The power is out front! So swing sooner, and hit the ball further ‘down the line’ of the swoosh and your pop-ups will be a thing of the past.