They're mostly backwards though
McTominay had only played 6 games I dont think anyone is really drawing conclusions from that. Fred had played 9, still not loads
Thing is, there is no way McTominay could have averaged 100 passes if those stats only include starts. Here's his first 6 starts in 18/19:
v West Ham 50 passes in 90 mins
v Newcastle 31 passes in 45 mins
v Southampton 64 passes in 90 mins
v Liverpool 31 passes in 90 mins
v Palace 55 passes in 90 mins
v Southampton 47 passes in 90 mins
I'm no statistic expert but the above numbers clearly don't add up to 100 passes per 90 minutes. The only way to have such a silly and ridiculous tally is to include sub appearances where he makes plenty of passes in a few minutes.
I have no intention in bringing McTominay into this topic, I just want to use this as an example to show that there is a
huge sampling bias in your stats. This also applies to Herrera, to a lesser extent though as he plays more games, but still those stats are hardly valid for comparison.