To simple answer is it doesn’t matter when it comes down to body composition. The calories burned from your cardio regardless of when they are done (fasted or non fasted/pre or post workout) will all be added towards your total kcal deficit.
The deficit is what is utilising body fat, not the type or the timing of the cardio.
If I were to choose my preference it would be either post workout or early morning to ensure it doesn’t take away from weight training, energy and performance.
If I was recommending cardio for a client it would be to schedule it in whenever it is most convenient to their own individual schedule.