Sourdough is such a satisfying hobby! I’m always floored at the $10 loaves for sale at my grocery store. I guess people must be paying otherwise they wouldn’t be pricing them that high?
Judging by the 36 hours you may have already done this, but if not, to tease the most sour flavor go with a cold slow ferment in the fridge. I let mine go overnight in the fridge about 12 hours or so and then bake in the morning. Something about favoring the lactobacillus vs yeast when in the fridge helps bring out the flavor.