Man, my buddy Dave went through this exact thing last month. He was ready to toss his air fryer in the trash because his fries kept coming out like little potato sticks of sadness. Turned out he was skipping the oil spray too and just dumping them in dry, which is the whole problem right there. Once he started giving them a light coat and shaking the basket every few minutes, night and day difference. Your 400 for 14 with a shake sounds about right to me, that lines up with what he landed on after a few tries.