I am looking for answers to a few specific questions (at bottom of post) but also, and maybe more importantly, any additional comments on those things I don't even know to ask yet.
Finished Loaf:

Crumb Shots (different parts of same loaf):


The story (aka the method, and what went wrong):
This was intended to be a 123 No Knead Do Nothing loaf, according to the recipe here on this site: http://weightloss-slim.fit/node/56678/123-sourdough-no-knead-do-nothing-bread%3C/a%3E%3C/p%3E%3Cp%3EI used 100g levain KA AP flour starter at 100% hydration, 200g filtered water, 300g KA AP flour, and 6g salt (salt is adjusted just slightly down from recommendation cuz I watch my sodium intake). My room temp is about 70F.
3- Do you think it is overproofed? underproofed? Or just about right?
7- Any other comments or advice very much welcome! Thank you!
I can't help you with all of these, but I'm sure it's a bit underbaked. Everything else about the bread looks pretty good for your first one! The dutch oven is a solid technique, 20min lid on, 20-30min lid off, or to your liking. Cast iron DO results in better color than just a big stainless steel pot with a lid, but both work just fine, and way easier than trying to steam your oven, which I think is more likely to cool the oven too much than help. Shaping is tough, takes time to get good at, and your 71% hydration recipe is best for your second or third loaf.
Thanks so much for your reply!
I don't own a DO nor any other cast iron at all, and with the current situation, not in a place to buy one right now. It's on my list, though! In the meantime, I'll just have to make do with what I've got, but maybe I can find a cheap stainless mixing bowl to use as a lid on my baking sheets.
I'll let it get darker next time for sure!
Target shipped me a Lodge Cast Iron Dutch oven combo for $50. It's $40 now
https://www.target.com/p/lodge-3-2qt-cast-iron-combo-cooker/-/A-46987382
Planning on my 2nd loaf tomorrow. Anyone have any additional suggestions to add before then?
This one. You've probably seen it already. I'd take this quote to heart:
If you are new to sourdough baking and decide to bake this recipe as a loaf for learning, please do your best to follow the recipe as written. Changing things on your first bake will add variables that can complicate troubleshooting. After you have successfully baked this bread as is, you will be better prepared to venture out with this formula or any other as you wish. Experimentation is at the heart of all avid bakers. But it is most efficient if you learn to walk first, and then run.
I remember when I started out getting into trouble when I deviated usually because I got distracted. When I didn't get the results I wanted even after following instructions to the letter, I fell back on "watching the dough, not the time".. And then I usually got an acceptable result. We're all pressed for time but all good cooking/baking takes an appropriate amount of time.
I'm quite sure the author of that quote did not mean I should ignore the dough and just randomly pick any amount of time in the rough time windows the recipes gives. Part of that recipe is about learning how to "watch the dough". I'm asking for help in interpreting how well I did with that. I'm asking for help in understanding why the dough was so unmanageably sticky and what to do about it.
I appreciate your advice. If you read my whole post you know I didn't set out intending to deviate from the recipe. I added the retard because it seemed the best option I had when my levain nearly doubled much faster than expected. And I proposed the possibility of adding slap and folds as a way to get the stickiness under control. You might be right that I should not do the fridge retard nor add any working of the dough. But I feel it will be very difficult to progress without some feedback on the difficulties I encountered, my results, and how to improve.