I grind my own grain at home and make my own bread. 100% difference from what's available in stores vs. at home.
You'll never find any of the artisan-style almost-burn loaves that you see on pinterst using 100% whole grain. Will never poof up like that, you'll get something closer to German-style brown breads.
They pull the wheat germ -- essentially the plant embryo, but also a source of nutrients that can go bad -- out of the flour to extend shelf life. Ditto for taking out all of the bran -- fiber! -- though "whole wheat" flours will add some of that back in later. But for the most part modern breads are nothing but refined carbs with a touch of fiber.
The germ is sold separately, as a health food or feedstock for animals.
The difference in taste and shape is noticeable. It's also much, much more filling and satisfying. Not as great for avocado toast, but does pretty well with a little cream cheese and tomato (plus a pinch of salt).