Yes, you can improve mobility and squat heavy.
Mobility is a full body approach to address elements which limit movement and performance.
Improving mobility translates to getting in better positions which translates into achieving ideal positions with technique.

Getting into ideal positions with technique will not limit performance.
Mobility is an aspect of performance which is worked on continually.
10-15:00 minutes a day.

There are several episodes which focus on squatting.
Do you have trouble/tight areas?