My sourdough turns into a pancake when I tip it out. What am I missing?

I’m four loaves in and they all look promising in the bowl, then spread sideways as soon as I turn them out of the basket. The dough feels strong after the folds, but by shaping time it’s sticky and hard to tighten. Yesterday’s loaf was 75% hydration, bulked for about six hours in a warm kitchen, then went into the fridge overnight.

I keep seeing completely opposite advice: use less water, build more gluten, or stop bulk earlier. I don’t want to change all three and learn nothing. What would you look at first, and what should I record on the next bake so I can tell whether it’s hydration, weak shaping, or over-fermentation?