I can see your point and I agree. It is possible that a weaker player/team can beat a better team, happens all the time in sports in real life.
That's a good argument about Zeus. I would say he was the better player too despite losing before Tanageshima got his semi-finals upgrades.
Sanada couldn't use Lightning (Rai) because it was sealed for Tezuka. So Kanto Ryoma is better than Kanto Sanada.
If you use Nationals Sanada (w/.Rai) against Nationals Ryoma (PoP) then he still loses.
Sounds like a lot of excuses for the losing players. It's okay if they lost, maybe they can win next time...
And Sanada beating Ryoma 6-0?! Impossible...