Crispy crust for days?

My crust is pretty chewy, even as recently baked. After the first day it doesn’t get any better. I store it cut-side down with no cover. It softens up if covered, but also lose a lot of flavor.

I sometimes buy sourdough bread from bakeries and they often got a very crispy crust, almost like crackerbread, and it stays that way past the first day.

What is the secret to something like that? Their loaves are typically quite charred. Is there anything in the dough preparation from mixing to cold proof or is it mostly baking? I usually bake on 235C over/under heat, 20 minutes inside a Lodge Combo, 20 minutes without the lid. I’ve thought about reducing time under a lid and increase the time without one. I could of course let it bake longer without the lid, but if it’s already 96-100C inside, will that have some negative impact?