Exactly, it's not like Bernardo Silva wins big games for Portugal. Or Dias looks like a world beater. Look at Cancelo this year at Bayern, this is a guy who was one of their players of the season last year. It's exactly like you say, they just play in a system that extracts the most of their best attributes and hides their weaknesses. People always talk about players level like it's an absolute. When in reality, top players are good at certain things, great at others and average at the rest. The environment they play in from system, teammates, league, etc will usually decide the level of their overall contribution and ouput. The exceptions are so rare and you'd have to go to a really rare breed who are not as affected by the aforementioned factors.
Fair enough! I also rated Gündogan highly back then but it was also the caveat that he was playing for a Dortmund team whose players could up in the Hummels and Lewandowski category or the Mkhitaryan and Kagawa category.