What makes you think the NFL doesn’t have AEDs in their stadiums? They used that on the field in this situation.
2 things:
1. I saw no report as such and reports of the duration of cpr does not support AED use on Hamlin,
2. If they used an AED and were still required to maintain cpr for the duration reported to keep him alive, we don’t have all of the facts...and I would argue that he’d have failed a pre-game physical.
When I saw the video, it was clear that speculative (damage control) reports did not match what happened because he recovered from the hit and rose full standing before dropping like a rock.