He will do just fine. His skin is like lycra already anyway. The thing i wonder the most is if he wins Tour 2022 should he do Vuelta 2022. My mind says no but the heart says yes.
Hard decisions.
It's a dream scenario though, right? i.e. winning the Tour would be the pinnacle of his career & he'd be able to take a step back & ask himself what he wants next. But IMO only doing one grand tour would be a waste of his peak years, so win or lose the Tour, I'd expect a Vuelta challenge for number 4.