Flexen wasn’t part of the Bummer trade.
Shuster was the only real get of the Bummer trade, plus the role of the dice on Soroka. Lopez, Shewmake and the other minor league pitcher were obviously just filler. Not sure what kind of return any one could reasonably expect for a reliever coming off a 7 ERA season, but if Shuster takes a rotation spot, to me that would be a won trade