Decided to try baking sourdough for the first time, and here's the crumb of my first two loaves! They were delicious, but both gummy, and I can't tell what caused it!

Both are made with the same recipe, but proofed differently.

Basic recipe:

110gr whole grain rye starter (and a bit of dry yeast because it's still quite young and not active enough, maybe max half a teaspoon)

325gr water

500gr flour

Rest for an hour, add 12gr salt with stretch and folds

Half an hour later stretch and folds again

Then do 3 sets of coil folds every half hour

Here's where the two doughs differ

Bread 1 had a total bulk fermentation time of \~8 hours from mixing together to being shaped, at maybe 22 C and put into the fridge in an benneton, where it stayed overnight.

Dutch oven was heated in the oven 250c, temp reduced to 230c when the bread went in.

Bake at 230c for 30 minutes, then uncovered at 200c for \~25 more.

Bread 2 was left outside for roughly 13 hours, but at 19c (i fell asleep lol) the dough was very jiggly, had more than doubled, big bubbles, and stringy out of the bowl (so overfermented?). I put it in the fridge for only a few hours, then baked.

Dutch oven heated in the oven at 250c, reduce to 230c and put the dough in. Left it covered for 40 minutes (made the relaxing cut 6 minutes into baking), then uncovered for 25min at 200c.

I'd say bread 1 was under-fermented and bread 2 over-fermented, and I baked bread 2 for longer because I'd assumed the gummyness came from underbaking. Bread 2 is denser and gummier tho. 

I found varying results weather under- or overproofing causes gumminess, and I can't figure it out fully. I plan on baking my next bread soon, so I'd love to figure out what to so next.

Why are my breads gummy?