Is there a coach at your gym that can help you?
Sounds like you need to address your quads more than once a day. As the situation improves you won’t need to spend as much time, but in the beginning your body needs the reminders.
Placing a weight under your heel creates slack in the system which is why you can squat easily with a weight under your heel.
Everyone is different some people may have upstream restrictions some may have downstream restrictions some have both. Address where you will see the most change first.
Have you watched Roop and Jami’s ankle& hip adventure 5 part series?
Free Your Heel, Free Your Mind
Ankle Positional Fault Fix: Jill Miller Style
Episode 303: Going Around The Ankle at MBSC
Episode 285: Sliding Surfaces; Ankle Range of Motion Case Study Part 1
Episode 285: Sliding Surfaces; Ankle Range of Motion Case Study Part 2