There's a lot going on here. Good job identifying some of the issues on your own. You are mostly fighting for a too-vertical back angle during this reps. Having your chin up and overextending your back on the way down are making the problem worse. Let's prioritize a little bit: First, before you start moving on each rep you need tight abs and eyes/chin down. Both of these are critical. Then as you start each rep, you need to simultaneously reach forward and out with your knees and point your nipples at the floor, right away. This is going to help you set your back angle and knee position early so that you can more easily bend over and reach back into the bottom position.
Getting your knees set in place by halfway down and getting a nice horizontal back angle are part of what make the low-bar squat an intentional, contrived movement, meaning you can't just squat down and stand back up. Check out the "How to use the TUBOW" video on YouTube with Jayson Ball. It's a drill that should help you as you work on these things.