Nope. I always look at BB like taking a hard class where a textbook is available but not needed for the class. The book can give you pointers that may help you but it is by no way cheating. Now if PL games helped build up your enthusiasm or something then they would be deemed unfair because they give you an in game unfair advantage. Having more resources (more games in your PL) is useful but not violating any rules. Some people may disagree but when it comes straight down to my league games regardless of what I do in my PL it gives me no real advantages for inside the actual game.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs