I remember people saying that Boaster hadn't actually proved himself as a great IGL because "he needed a superteam" to win a trophy. But when we look at the winners of each international event, most of them had teams we would consider superteams in their own right.
The only exception might be Acend, but even then they had cNed, and starxo and zeek who were popping off at Champs 2021, so you could even count them.
I know Fnatic had an amazing squad but that shouldn't take away from Boaster's ability to lead a team