Maybe counting errors is the wrong thing to compare. I guess it's just something about those Zverev 2nd serve yips that makes me cringe continuously in this match in a way that that Federer Millman match (for example) didn't.
But this is a ridiculous hypothetical. When would Federer ever be making errors at this rate? Maybe when his back is completely shot? I mean Federer-Djokovic in 2019 wasn't the highest quality match ever, but compared to this?