He needs to be a lot sharper than he has been this year so far, but at least he's playing better than 12 months ago. By the time we made it to late December & January last season, he was playing at a much higher level. We'll see if he can pull off similar improvement by the end of this season.
What's interesting is it seems like defenses are having more success this year than the past. There are only two QB's with significant playing time who are above 70/100 QBR on ESPN's list and Mahomes is one of them, despite his struggles this season. Tua doesn't count, given that he has missed a lot of time. Everyone else is 68/100 or lower in the list. Justin Herbert threw 57 passes last night without a touchdown. In 2019, there were 7 QB's who finished a 16 game season above 70/100 QBR on ESPN. This season it looks like that number will be 2 guys at most.
https://www.espn.com/nfl/qbr