1 - Find a good powerlifting gym. Nothing will beat in person technique feedback from a 800+ lb squatter.
2 - Failing (1), find one on the internet that does online coaching. Film yourself and pay for feedback. I have no experience with him, but George Leeman is strong as hell and knows his technique. You could start here. https://www.muscle-massochist.com/services/
3 - If you're in sf, I have a strong recommendation. (Your username may be old.)