First Two Loafs - Advice Needed

I baked my first two loafs and need some advice. The first loaf had a decent rise but the second was pretty skinny. Both turned out dense and gummy. Would love some advice for my next attempt.

The process I followed: 200 g of starter, 750 g of warmed water, 22 g of salt 1000 g flour (936g unbleached bread flour and 64g of whole wheat, I thought I had enough flour when I began and was already too late in the game to abandon the project.. I’m in the south with the snowstorm getting more flour wasn’t doable at the time).

After combining everything, I let it rest for an hour at room temperature.

Then I performed four stretch and folds. At the end of the fourth it did not look like any of the example photos on the tutorial I was watching so I performed two more stretch and folds until I got to what you see in the last photo.

Next, I let it rest at room temperature for an hour, then divided it into two loaves and formed them into boules. I placed my two boules in their bannetons then placed them in the fridge for 8hrs-9hrs.

I preheated my oven and Dutch oven to 450°F for one hour before placing my first loaf in to bake. I baked the loaf covered at 450° for 20 minutes, then uncovered for an additional 30 minutes the internal temperature when I took the loaf out of the oven was 212°F. This loaf was the one with better rise in the photos (the one on the right).

While the first loaf was baking, I kept the second loaf in the fridge. I repeated the steps for baking the second loaf as you see above and made sure to keep the lid of the Dutch oven inside the oven during the first baking process.