Generally speaking flavored coffees are made from lesser grades of beans. Same with very darkly roasted coffee. Why use expensive specialty beans if you're just going to burn them or cover them over with added flavors? It would be like over-cooking a Wagu steak and/or covering it in ketchup.
Not that there's anything wrong with either of those choices. Lots of people just drink instant coffee or put ketchup on their steak. It's just a choice.
I had a roommate for a while who was a coffee nerd. He had so much equipment and really knew coffee inside and out. He spent a lot of money on the beans. He would drink
Fabula coffee throughout the day but would switch to decaf at some point in the afternoon so it wouldn't affect his sleep. Sometimes he'd give me a cup and challenge me to say whether it was regular or decaf and I could almost never tell, at least not until I had consumed a good portion of the cup and noticed the affect the caffeine, or absence of it.
So I know there is good decaf out there.