What did I do wrong?

M starter is active. I fed it the night before and use it the day after following this recipe but accommodate a night in the fridge and I did not split into 2 loaves: https://www.farmhouseonboone.com/how-to-make-whole-wheat-sourdough-bread

1) My flour was whole wheat from a local Mill and a cup of type 1. It was very hard to mix it and I decided to knead it too. I did several stretch and fold following the instruction. Set aside for rising and almost exploded. I was really happy. I had to put it in the refrigerator because of lack of baking time. So I shaped it and put it in the refrigerator overnight (about 16 hours). Took it out and score it, the bottom looked a little dry and it did not rise in the fridge at all. Pictures show the results. It basically exploded because the fracture is half done by the scoring but half "spontaneous". Taste is incredible but I would say...may be under cooked? My questions 1) is bread like this "edible"? 2) was the temp too low considering that I did not split into two loaves? 3) was the cooking time to short? 4) what should I do with this bread (I hate throwing away food)? Thanks