You are getting to depth fine in the first vid, for most reps. That falls apart a bit in the last vid, I assume cos you are using more weight. I see an extra 10kg plate in the last vid.
Stance may help, but I suggest that the main issue is mental discipline. Just make sure you go full depth on every single squat, from empty bar up to final work set. You may go “backwards” with weight and/or reps for a bit but you will get stronger and push past where you are now, probably in just a few weeks.
Pretend you are “squatting” Kate Upton. You don’t wanna go shallow. Ever.