I suspect you might mean DFW where you have DTW? DTW (Detroit Metropolitan Wayne County Airport) is a DL hub. DFW is AA, and oneworld.
There's nothing wrong with your 'backtracking' within the US, nor your European segments. You have 3 intra-Europe segments on the end and 1 on the front (OSL-DOH). You also aren't exceeding the stopover limit.