First Sourdough in a While

First time making sourdough in a while. Have gotten better ears/oven spring in the past, not sure what was different this time. Critiques welcome!

Recipe (makes two loaves):
200g starter
900g KA bread flour
700g water
20g salt

Mix started, flour, and 650g of the water, leave for 30m to hydrate. Add salt and remaining 50g water and mix. Stretch and fold every 30m for 2-3h. Divide and bench rest 30m. Shape and put in banneton. Cold proof in refrigerator (first loaf had 8h in fridge, second had 24h). Bake in Dutch oven @ 500 for 20m covered. Uncover, drop to 450 and bake another 15-20m.