This is interesting to think about. There is some selection bias in these numbers.
First of all, like another poster said, Buxton has the "good fortune" of not playing many games with the 2021 team so far, which weighs this sample toward our far better seasons of 2019 and 2020. But there is no Buxton W-L magic in 2021 thus far.
Another factor is when Buxton comes off the bench. In 2019-2020, the Twins were 13-0 when Buxton entered a game off the bench! But when you think about it, it makes sense -- if Buxton is getting a day off from the starting lineup, they're probably not going to bring him in except to protect a lead. (The streak ended in 2021, of course -- we're 0-1 with Buxton coming off the bench this year.) Probably even more so for Buxton compared to other players because of his excellence as a defensive replacement.
Buxton also misses more time than other players, so his sample of games started is smaller and thus more prone to variance, I suspect? The guy more likely to have IL stints is more likely to have missed any given stretch of games -- could be hot streaks, could be cold streaks, but the smaller the sample, the less likely any imbalance is going to even out.
Here's our 2019-2020 win-pace when various players were in the starting lineup:
Buxton 107.5
Garver 105.7
Gonzalez 102.9
Rosario 102.2
Polanco 100.6
Cave 99.5
Arraez 98.9
Kepler 98.3
Cruz 97.5
Sano 94.9
No doubt Buxton is a good player and an important part of the team, and I'd definitely like our chances with him in our lineup over Sano, but our team had a 100.0 win pace over those two seasons, so I'm not sure if these numbers really represent much other than mostly random variation around that number?