Hard, thick crusts

Hi everyone,

I've been enjoying the sourdough life for about 2 years ... of course I think I made the first loaf that I was happy with about a year in (that's a lot of sinkers and loaves that went into our food waste bin), and for about the last 6 months I feel I've really got it, and have been making consistently decent loaves that have found their way into both my and my loved ones' tummies!  

The only part of my loaves that I am unhappy with is my bottom crust.  No matter what I do, my loaves tend to have a very hard, thick bottom crust that I almost have to go out and get the wood saw to cut through. Never have I had that nice chewy crust that I'm used to purchasing, I'm actually surprised I haven't chipped a tooth on some of the bread I've made!  Here's my usual recipe and process:

970g flour (mostly white, sometimes including approx. 150g of rye, whole wheat, whatever I have on hand)

30g essential wheat gluten

800ml water (dechlorinated)

200g starter that's at least doubled in size and is still on the rise

20g salt

Combine flour and water, let sit for 30-60min

Add sourdough starter and salt, fold in and let sit for 30 min

Do approximately 4-5 stretch and folds at 30 -60 min intervals

Bulk rise (usually overnight in the fridge)

Remove from fridge, allow to sit for an hour before final shaping

Sit at room temperature until doubled (approx) in size

Place in dutch oven that's been preheated for 30-60 min at 500degrees F.

Immediately turn down temp to 450 for 30 min, and bake for 30min

Turn down oven to 400, remove lids and bake for another 20min or until dark golden brown on top.

Remove dutch ovens from oven, allow to sit for 10 min before removing bread and cooling.

Am I mising anything or am I doing something wrong? Any assistance would be appreciated.  I'm spending my Covid-19 time baking bread and knitting, and i know my friends who don't bake would be thrilled to get loaves that don't make their teeth break either!

Thanks!