Speaking of advertising, I believe Barcelona were the biggest club to hold out the longest against finding a shirt sponsor. They finally gave in and got Qatar Airways in 2013 and then Rakuten in 2017. That'll change over to Spotify this July, and they're even renaming the stadium to the Spotify Camp Nou.
Fun fact, Barcelona actually put a "sponsor" name on their jersey starting in 2006, but it was to advertise Unicef.
..and to stray off topic, I was thinking about Ronaldo earlier today (R9, not Cristiano) and how he played for rival clubs twice, first Barcelona and then Real Madrid, and Inter Milan and then AC Milan. But I don't remember there ever been a huge outrage, like when Figo switched from Barcelona to Real Madrid for example.
I might be remembering wrong