Getting torso more vertical on garland (squat) and chair poses

Does anyone know how I can do that or what I could work on. It seems like impossible for me to get my torso higher than 45 degrees, if even that high. I don’t think the problem is in my ankle/shin angle. I think it is the inability to straighten my torso at the hips- what part of my body is weak?

thank you!

try to lift your chest rather than pushing from the hips. spread your knees apart as much as possible make sure your thighs are not blocking full expansion. Try to position your arms as low as possible on the shins, and grip your hands as high as possible

Practice locust posture to build lower back strength