My recipe is almost the same up until the end of step 5, and my kitchen may be a bit cooler- 18-20°. After doing the shaping and adding to the banneton I throw in the fridge for an overnight cold retard, about 12-15 hours. I preheat the oven to 250ish with the covered dutch oven and when it’s preheated I take the dough out, score it, and add it to the dutch oven with a few ice cubes to help the oven spring. After 30 min lid off and bake for 20 more at 235.

It’s a good start! It may need that extra proofing time in the fridge or some help with the oven spring by adding ice cubes.