Critical care paramedic here. The answer is "both".

AEDs are a key factor in ensuring patient survival until we can get them to the cath lab and get them ballooned.

"High quality compressions, early access to defibrillation". For every minute you do not have an effective pulse, your chance of survival goes down about 10%.

Airway management takes a distant back seat. Most meds we give are only mildly, or questionably effective.

But being able to defibrillate a dysrhythmia early is the key to getting the heart working itself - chest compressions are the best we have, but still. It takes us minutes of compressions to get to a suitable arterial pressure for effective perfusion, but ten seconds or less to lose it.

AEDs won't improve volume and arterial flow, but it'll give you a fighting chance of getting to the lab. Compressions alone are not going to do that - they will just preserve tissue.