Yes I find it weird how Real Madrid are going to be able to go on another huge spending window, same with Utd actually, where the f is all this money coming from?
It's their revenue streams. Both Madrid and Utd are global brands with huge followings and make a lot of money, so in theory they spend within their means. Madrid also benefit from the way the Spanish TV money is split, with most going to them and Barca.
Meanwhile City don't make anywhere near the same money from merchandise, gates etc., and have artificially increased their sponsorship deals in order to try and bypass FFP - which was never about capping spending as much as making sure clubs spend within their means. Essentially City have had to, in their execs own words, come up with "imaginative ways" around the spending rules.