u/Dee-kay-2303

This is my 5th attempt.
The bread itself tastes good and has a good mouthfeel. But it just never comes out airy and always seems a bit gummy, dense. Any tips for improvement is welcome.

My recipe

300 gm flour mix of 50-50 bread flour and Whole meal flour ( I don’t use 100% bread flour due to gut sensitivity)
204 gm water
70 gm starter
6 gm salt
After initial mixing and slap and fold, I do 2 sets of stretch and folds 30 minutes apart and 2 sets of coil folds 30 minutes apart. Bulk fermentation until 45-50% rise in volume. Internal temperature of the dough at my home ranges from 26-28 deg C. Cold proof for 12+ hours, then baked at 220 deg C for 20 minutes and 210 deg C for another 20 minutes. I open bake my loaf.