Keep getting closed crumb on High hydration (85%) dough

How is everyone doing? My high hydration sourdoughs never seem to get those big open holes in the crumb even with a high hydration like this. I use  350 grams of flour, sometimes I add in some whole wheat sometimes I don’t but no matter what I always seem to get these dense crumbs. For this particular loaf I gave it a 2 hour autolyse, a  1:2:2 levain that more than doubled in 4 hours, 4 coil folds in the first two hours, then bulked for a total of 4 hours. Then I shaped it via stitching and baked it straight out of the fridge after 18 hours. But yet my crumb looks like a much much lower hydration loaf. Any ideas on what went wrong? I may not have scored it deep enough I think my razor was dull but that surely couldn’t be a reason right? Thank you in advance. :)