Im not sure about zwift, but trainer road has tons of stuff that mimic enduro stuff. intervals of around 4 mins with sprints and the like. with recoverry inbetween. My go to on TR is sufferfest violator. 5, 10 and 15 sec intervals. if i can finish that with good power, i know im on for a result.
As mentioned before though some base miles help with energy across a weekend, and recovery. Outdoors, i tend to target uphill sprints on strava of around 40secs, this helps when there is any kick ups in a race.