Do I need more fermentation? Why my sourdough is flattened? From a few weeks I've been trying to make sourdough. The most successful recipe for me and for the time I have I found is Easy Sourdough Bread Recipe using a stand mixer - Sourdough Lamination In the recipe it said that it needs 3 hours in room temperature + 30 min in refrigerator and then you bake.
Because I don't have that time in one I leave it on the counter for 1 hour then let the sourdough in the refrigerator overnight (10 hours) and bake it in the morning. The whole wheat flour I use is with 13% protein.
I found the dough &quot;flattened&quot; and without so much holes and somehow I feel like it's not so fermented. Is it possible for 10 hour fermentation in the refrigerator? How can I improve the dough and do I need more fermentation time maybe in room temperature? The dough is fine, not so wet it can be shaped. I added picture in the end to show what I mean.
The recipe is:

200 g. white flour
100 g. whole wheat flour
240 g. water
6 g salt
90g starter
40g pumpkin seeds

Totals:

345 g flour (45 from starter)
285 g water (45 from starter)
2% salt
82.6% hydration
First of all, that's quite a decent looking loaf. It doesn't look dense or overly pancaked. The crumb is consistent, with good bubble formation. A lot of amateur bakers would be quite proud to achieve that result. So give yourself a pat on the back before you start trying to improve further.
Now, 82% hydration is quite high, even for a whole wheat loaf. High hydration free-form whole wheat loaves are notoriously difficult to shape well, simply because the dough is so loose. Careful shaping and skillful oven control (including steam) are necessary to get a good loft in those circumstances.
Now, three hours at room temperature is not enough time to develop significant sourdough taste. Neither is ten hours in the refrigerator. (Ten hours in a cool room would be closer.) As more fermentation occurs, however, the gluten structure will weaken, leading to a flatter loaf.
So overall, I'd suggest you try a lower hydration and a longer cold rest (but, if possible, at a slightly higher temperature than your refrigerator).