No, Van der Poel, Vingegaard and Ganna are not in Pogacar's league.
If everybody starts fit, in form, no accidents:
Sanremo: Topfavorites Van der Poel and Pogacar, but others can win. Despite Pogacar being winless, he has to be a favorite every year.
Flanders: Topfavorites Van der Poel and Pogacar, with Van Aert, Pedersen as outsiders
Roubaix: Topfavorite Van der Poel, with Pogacar at his debut as big danger
Liège: Only Pogacar and Remco can win. (Unless something changed in the last year)
Tour: Only Pogacar and Vingegaard can win.
WC: Rwanda seems perfect for Pogacar
Lombardia: Pogacar clear main favorite
That's what sets Pogacar apart, he is one of the, if not the favorite in every race. Does that mean he can't be beaten? No. He could end up winning none of these races. But unlike the others he can compete for the win everywhere. And for the moment he does win. Different league.