First off, remember that you want to stay at or below your AeT, which is the upper bound of zone 2. Based on my experience it’s helpful to sustain a slow-moderate pace that keeps you in zone 1/2 depending on the terrain (I run flats but sometimes have to hike/walk up hills during AeT workouts).
As for the volume, you’re going to need to increase that number to at least a few hours per week to start and then gradually up the volume as you adjust to the training load. The only way you’ll see real gains is from consistently doing a high volume of AeT work especially if you think you have ADS—as Scott J, Scott S, and Steve have all discussed in their articles. Generally speaking, it’s hard to put a number on training hours as it is quite dependent on your goal/objective.
Lastly, I couldn’t help but link Scott’s deconstruction of the word ‘cardio’ as it relates to endurance training – https://uphillathlete.com/dont-call-it-cardio/