I played 2 matches tonight against both teams that were 86 ranked. Won the 1-0 against the one team with 31 Chem. Lost 1-2 against the other team with 27 Chem.
They managed to completely break World Class difficulty, worse that it was 4-6 years ago when some people back then argued that Legendary was easier. But in FIFA 21 - FC 24 versions, they FIXED WC to clearly be less difficult than Legendary, which it should. This WC difficulty is frustratingly ridiculous when facing 80+ ranked teams. AI never stops moving at full speed in any direction. I can deal with that, but it's the tackling. Just way too overpowered. They expect you to always pass the ball in complete open space and keep that open space when attacking the goal at the speed the AI players move? The open space won't happen, so you will be dribbling near them. Can't do anything if they tackle and end up winning the ball EVERY time.
I would just play Professional, but it's much easier to a fault and the points reward are too low, especially with just 12 + 2 games for points competition. I have been playing WC for years and feel I shouldn't have to completely relearn this game and its strategies to just barely end up winning, if that.