Reworking Sourdough Techniques

Few weeks ago, I posted on here asking for feedback on my sourdough bread as can be seen here: https://www.reddit.com/r/Sourdough/s/WxlpCdu6jz

I feel like I have improved somewhat but still want to initiate another feedback loop of suggestions. My ultimate goal is to have as airy a crumb as possible while still having a sizable percentage of whole grains.

In the above loafs, I have both used 450g of flour but one is 1/4th whole wheat and one is half.

As per the suggestions last time, I have cut out the rye completely and increased the water percentage.

I also fed my starter 2 cycles ahead of use instead of 1.

My current technique is as follows:

450g flour (ether 1/2 bread or 3/4 bread with the rest being whole wheat)

360g warm water for 1/2 whole wheat loaf and 340g water for 1/4 whole wheat loaf.

1 tsp diastatic malt powder

125 g ripe sourdough

11g salt

I combine everything but the salt and let it fermentolyse for at least 90 min. I then add the salt and do 4-5 series of stretch and folds 30 min apart. I then let it bulk ferment for 6 hours at room temperature.
I then shape and put in banneton in the fridge for about 18 hours.
I preheat an oven with a Dutch oven in it at 480f. I plop my cold dough in, slice, spray water and bake with lid on 20 min. I take lid off and reduce temp to 460f for 30 min till it’s the color I like. Set on the counter to cool.