I have a tendancy to pick and choose my way through this discussion
My experience tells me that reverse thrust is difinitely a component of net thrust counter to forward thrust. Typically diverted forward at 45 degrees.
According to the explanation in the NASA discussion above (a good job of explaining) the inlet drag is significant to the total net thrust and always acts as a braking (against forward thrust) action in the typical subsonic jet.
I accept the explanation that a working engine does slow down the air and does increase the inlet drag contribution.
I submit (slightly off-topic) that a windmilling engine does not have the same significant internal air blocking (the burner is not working) and as such the drag component will be less. I also surmise that a seized engine (locked rotor) will not have the internal pressure blockage (from a still working compressor) and as such the inlet drag drops to mostly the efffect of the inlet minus an engine behind it (less yaw).
I expect that not all will agree with me
