Well, he's not actually closing, so that was likely the Phillies' farewell gift to him. (And also it was more the Phillies' fault that they never found a better closer - not for lack of trying!) Plus he's got a better coaching staff and manager now.
And even if he does have a bad few weeks, who doesn't really? Dude just ends up being pretty good (and even more incredibly, healthy) by the end of every season (2018 was the one exception. 2020 he presumably would have been fine over another 102, and had an incredibly low FIP/no home runs over the 60).
Right now he's so off the charts good that it's surely not sustainable but he could literally double his WHIP and still be great.