Thoughts on gran fondo training plan?

I’ve started the 8-week gran fondo training plan on zwift. I know that a lot of you think the zwift training plans are trash, but i really like the smooth process of having a workout ready for me in zwift.

However, I’m on my second week, and find the workouts to be quite heavy (a lot of zone 4/low zone 5, and zone 3/2 between).

Does anyone have any thoughts on this training program? Am I wasting time and energy here?

I’ve considered adjusting my ftp down to make the workouts easier. Right now, it’s set to 230 which is my ramp test result.

FYI i’m training for a triathlon ironman 70.3, and am quite unexperienced with cycling. My overall shape is good.