Great example of how large the spread between bWAR and fWAR can be, not just for a season but for a whole career: our old friend Rick Porcello.
Career bWAR 18.8
Career fWAR 29.6
That's large!
In his final season, the short one of 2020, Porcello had a grisly ERA of 5.64 in 59 innings, but a FIP of 3.33.
fWAR - 1.6 - ace level!
bWAR - 0.2 - barely above replacement level!
Since he never pitched again, did teams reject the usefulness of fWAR for pitchers?