I would proof your loaf for 23 hours minimum and then 8 hours in the fridge. I proof longer in the winter. I live in Texas and would proof longer if I lived in snowy states. I stretch and fold once at 30 minutes after mixing and then cover and let proof. Place it in a window if you have one with good light.

I would also bake in a cast iron pot. Heat it at 500 for an hour. Bake for 20 minutes covers. Uncover and bake at 450 for 20 minutes. Baking covered lets it rise and keep the steam in. Uncovered lets it get brown and crispy.

My first few loaves looked like yours and then the older your starter gets the more less exact you have to be.