Welcome to the UA forum.

The altitude gain and time provided in training plans are generic and do not take into consideration your current fitness, goals, location, etc.

Based on your AeT focus on what is doable and then gradually progress over your training period. For e.g. I have a trail locally that gains about 2500 ft. over 3 km. Initially, it would take 1.5 hours or more to get up and slowly I was able to reduce the time. I would adjust volume (time) on other workouts in the week to meet my weekly goal.

Hope this is helpful.