+1 for off season HIIT, short sessions but frequent. At this point I’m doing more than Justin even prescribes in the off season. Major difference in RHR and training endurance.
If anything I might end up starting next prep with lower cardio than off season. IMO hard cardio is more important in the offseason. You need to actively improve your body’s CV capacity as you’re pushing bodyweight, adding new (vascularized) tissue, and generally doing things that would otherwise harm your CV health.
Prep- probably just want to maintain CV capacity, assuming you kept it golden in the offseason doing the above. Then it becomes an as-needed tool to manipulate your energy balance.