Why do you want Romo and Clippard walk? They don't cost much and they are still quite effective. Why do you want Adrianza stay? He is really not that important and can be easily replaced by a prospect. Why do you want to extend Buxton for 8/$160 if he can't stay healthy to contribute?
I would rather keep May over either Romo or Clippard, and allowing those 2 to walk frees up $7.5M from what was committed this season. It isn't a matter of effectiveness, just a function of not being able to pay everybody.
Adrianza's contract next year would be a rounding error on the books, and his defensive versatility is worth a lot in my opinion. If he can hit more like he did in 2019 than this year, he would be a strong asset off the bench.
As for Buxton, when he is healthy, he is the most important player to the Twins and it isn't particularly close. Nick Nelson tweeted out the Twins winning percentage over the past couple years with Buxton in and out of the lineup and it is a huge gap. With 2 more years of team control, by the time Buxton would hit the market, it is very possible he is asking for Gerrit Cole money, and I think a deal could be worked out that would benefit both Buxton and the Twins. I am betting on him staying healthy and playing 140+ games consistently, which he obviously hasn't done yet. The Twins might be taking on more risk in this scenario, but the reward could be huge.