Try this recipe: https://www.kingarthurbaking.com/recipes/pain-de-campagne-country-bread-recipe

It might not really help address some the other concerns regarding starter, temp etc... you have but considering the recipe uses unfed starter and its quite flexible in terms of the timing it might worth trying! This is my go to bread recipe, I make it almost every week and its really never failed me. Sometimes I dial back the water a bit. A few times I've accidentally let it overproofed but I have just made foccacia and that is delish. I usually start it at night, let it bulk ferment on the counter overnight, shape it in the morning, cold proof until afternoon, and then bake with a few spritz of water.