On a whim, I threw together stew recently in my dutch oven. I didn’t use a slow roaster. Along with most of what you mention here I too added a glass of red drinking wine + leeks + shredded cabbage. I pre-roasted everything in the oven first, then I’d add them to the broth simmering in my cast iron dutch oven on the stove top. I seered 2lbs of sirloin tips in parsley, garlic, and butter before adding it to the pot. I didn’t use flour. I’d run out of tomato paste — having made chili recently — so I used a whole can of Campbell's Tomato Soup.
The pre-roasting made a huge difference on flavor and texture and the broth had a wonderful rich dark color.
More and more often I try to take time to cook in lieu of ordering something or nuking a microwave meal. As such, we purchased a deep freeze so I can store large batches of chili, stew, and stroganoff in small freezer-containers so we can take small portions to work during the week.