Most of it looks good so I’m being hypercritical here.
Your setup looks a little short in hip extension. Make sure you take your time on the bracing sequence before you start the squat.
Focus on loading the hips and setting them back just a little more before you bend the knee.
Its a bit difficult to tell what’s going in when you crash down after hitting your restrictions. Slow it down and hang out at the beginning of your restriction.
Rear ankle distraction looks like the band might be just a touch high with band placement on the ankle. Also consider elevating the foot as to make the distraction pull back and down. Get the and just below the malleolus.
The yoga block is a pretty aggressive heel lift can you do it with something a little thinner? Also consider compensating by holding onto the pillar with your hands and get your heels on the ground by keeping a slightly more upright posture. Counter weighting with a plate or kettlebell works too.
As far as the couch stretch working for squats look at it this way. 1 If you can’t start from a braced neutral position then you are starting from a broken position and failing in the tunnel concept. Neutral hips are a part of this and if you have to crank your glutes to get your hips to neutral that is Inefficient at best. 2 Tension in a part of the system is tension in the entire system. Your body is crazy smart so if it is over tensioned in the front it will balance itself out by holding on in the back. Think of it like your hamstring hitting the brakes to keep your hip flexors from completely dumping your pelvis foreword.
All in all best advice I can give you is keep working at it consistency is your best friend. Watch the environmental loads your putting your ankle under. I saw what looked like a flip flop or otherwise backless sandal there which might be a clue to your body resisting change. So if you do your mobility work and the next stimulus you put on your ankle is a junk sandal which requires you to curl your toes down or keep a stiff ankle to keep it on you’re not doing yourself any favors.
Hope this helps keep working at it.