You need to be careful about interpreting the average power needed for a Zwift race. It’s better to look at NP and VI. Most races start very hard, and will settle down. What you’ll find is there will times in any race that you will be working well above FTP, and even with an FTP of 4w/kg, if you’re not used to going for 5 mins at 5+ w/kg, or 1 min at 7-8 w/kg then recovering you will find it hard. The races are very rarely a steady state at FTP ride.
Quite often, it’s not the highest w/kg that wins the race. Often it’s the person that knows the course, knows when the really high intensity work is likely to come and knows where they can recover.
Yes, it’s a game. But with any game, you have to know how to play. Playing Zwift is as important as power. A new racer won’t crush an A race just because he’s got an FTP of 5w/kg if he doesn’t know what he’s doing!!
Top tip - work on your top end if you want to race on Zwift.