How does p-factor affect jet engines, if at all? If it doesn't, why?
Since P Factor is primarily variation of AOA of a thrust producing blade when its rotation axis is not aligned with the air stream, you should see some P factor in a turbofan engine, to the extent that the inlet flow strikes the front of the fan from an angle.
I say "some" because the cowl inlet is going to align the inflow to be more perpendicular to the fan face than if the fan was in the freestream (where it becomes just a propeller with lots of extra blades), but it's hard to say how much. In any case, the flow is probably not quite 90 degrees to the fan face at higher body AOA, so it's safe to say there is probably a little bit, but since P factor is not accounted for in turbofan installations, what P Factor exists is not enough to matter (maybe if you stuck a turbofan on the nose of a Cessna 172, you might notice some P Factor effect).
On a turbojet there will be no P Factor at all since the thrust is coming form flow accelerating out the burner can, hot section and tailpipe, not from lift producing propeller/fan blades at the front.