What's the simplest whole-grain sourdough to make?

I like a fluffy crumb as well as anyone, but I like a simple process with fewer handlings of the dough, even more. I like low-gluten rye (and I know I can grow it), but wheat is fine too (though  I've had less success in my garden), and probably any grain is of interest to me. I'm already comfortable keeping a levain alive, even for many years (though I did just kill my current one). I'm open to high or low hydration, etc.

Whatever gets me as close to possible to: mix this freshly milled grain (blend?) with water and starter, let it rise somewhere that already exists (top of the fridge is OK, but I'm not going to buy or build a proofer), knead or stir it once, let it rise again, and bake -- and turns out a yummy, healthy bread that isn't so crumbly it can't be used for sandwiches (I'm not looking for grocery-store bread, I just don't want it so prone to falling apart that it's unusable).

I’m interested in this as well. I’m new to sourdough bread making. I’ve always used a bread machine but I’m tired of it

I imagine your ground grain mix will have a lot of fiber.
Evidently the fiber in whole wheat flour interferes with gluten development, leading to less rise in while wheat loaves.
I am not a sourdough baker, or a whole grain baker, but when I was baking whole wheat bread every week, I added gluten to it.
This helped it rise almost as well as bread made with white
flour.

Here's a couple of my favourite basic bread recipes:

https://thenourishinghearthfire.com/2026/09/03/fresh-milled-flour-sourdough-boule/

https://thenourishinghearthfire.com/2026/05/04/fresh-milled-flour-sourdough-beginners/

Both of these use the stretch and fold approach rather than kneading.

I often just do one round of stretch and folds, which is similar to the schedule that you mentioned.

The beginners recipe is probably the best place to get started - it's quite high in hydration, so you can do minimal strengthening, bake it as a pan loaf, and it will turn out beautifully.

Hah!
Injera!
Ethiopian injera bread is made with teff, a grain which is way too small to separate the hull out.
Now is it a sourdough?
Well it can be made with sourdough starter, but the original starter is , well unique to teff.

Teff, is rather expensive in the US, but more important than the the particulars of injera, the real answer we get from this is: flatbread!
Ground up whole grains plus sourdough makes flatbreads.
While not a loaf you can slice, they are ideal for "sandwiches"
I think there are probably dozens of these breads, made from all kinds of grains.

As usual for Permies this is is AN answer to your question, but it goes a little sideways and outside the box...