How to extend training to 20-25 hrs pw

I recently asked a similar question although I was only looking into increasing weekly hours to 10-15 hpw

With this amount of hours I would think the advice would be quite similar: less intensity, more Z2? or extending your workouts with Z1/Z2 aerobic rides.

That being said, that’s a massive amount of hours. How much hours are you already devoting to training? And does that include cross training as well?