Sourdough all bubbly but final dough is not

Hello everybody!

Hope you are all safe and healthy during these challenging times.

I thought I post here because the community is so kind and helpful ;)

I have been baking bread for some years now but started using sourdough instead of yeast only recently (baked three breads only using sourdough). I used this recipe

https://www.theperfectloaf.com/beginners-sourdough-bread/

Even though my sourdough was all bubbly, the final dough has not had many bubbles trapped in. It raised wonderfully, but I love big holes in my dough. So I wondered what I might have done wrong. I did stretch and folds like I did when baking with yeast and put the dough in the fridge overnight.

What can I do to increase bubbles in my dough? Is this also a thing of the hydration also?

Your help is very much appreciated!

Thank you a lot!

Linda