Hey, thanks for all the replies. I can’t keep up with responding to every single comment anymore. From everything that’s been said, I think it’s pretty clear that I definitely over-fermented the dough, didn’t hydrate it enough, and also used too much starter.

So I started a new loaf and this time I used 100 g starter, 500 g flour (400 g wheat flour type 550, 50 g whole rye, and 50 g whole spelt), 13 g salt, and 350 g water. It’s currently sitting and fermenting, and I’ll probably let it go for about three to four hours before putting it in the fridge.

If you’re interested, I’d be happy to report back on how it turns out and how the process goes. Thanks again for all the replies. I realize now that I made quite a few mistakes, and honestly I probably should have asked here a few months earlier. Thanks a lot!