My personal experience is that I need to angle the inhaler slightly downward (only slightly!) in order to get the full dose of powder. I generally do a long full exhale and then inhale deeply over several seconds - until well after the powder should be gone.
Gary Scheiner recommended inhaling the Afrezza slowly (unlike me) after a full exhale. It might be helpful to read his review.
“Sipping some water beforehand and exhaling fully before inhaling really helps.”
I am not experiencing the lung congestion, and it does sound like it would be a good idea to talk with your doctor about that.