Centralization is the goal. Keep it up but don't push into severe pain.

You can also drop to a 2-finger or 3-finger grip instead of wrapping your whole hand.

Couch stretch is brutal but the absolute gold standard for tight hips.

Also pack your abs tight. If your core is loose, your body steals motion from the lower back.

I like using it after sitting at an office desk all day long before hitting squats.

Agreed. Light walking and some cat-cow stretches always clear my back tightness right up.

And come back with questions whenever. The Beginners board exists for exactly this. Welcome aboard.

This is a great checklist, thank you. Going to film a set tonight, swap the shoes, and deload that second day. Will report back whether it's the shift or just the volume.

Now that you mention it I did add a second squat day about a month ago. Maybe I ramped too fast.

Come back in another month and post the heavy re-test. Bet you put 5-10kg back on the top end and it feels lighter than the old 140 did.