Umpires intend to be neutral. Even when you look at the umpire scorecard the next day and see that an umpire favored one team over another, it’s almost never entirely against one team or for the other. The basic fact is that umpires miss calls, and a missed call has to go against one team and for the other, even if there’s no bias.
Now, there are things MLB could do, like give postseason assignments to umpires who are the best at their jobs instead of those who have been doing their jobs the longest, but let’s face it, that’s a good idea, so Rob Manfred isn’t likely to get on board any time soon.