When you compare the 2019 projections of both Paxton and Gray from Basebal Reference I don't see a lot of difference.
https://www.baseball-reference.com/players/p/paxtoja01.shtml
https://www.baseball-reference.com/players/g/grayso01.shtml
https://www.baseball-reference.com/players/g/grayso01.shtml
https://www.baseball-reference.com/players/p/paxtoja01.shtml
https://www.baseball-reference.com/players/g/grayso01.shtml
https://www.baseball-reference.com/players/g/grayso01.shtml