With 210 units a postbac of straight As won't help your cGPA much. But if you don't have recent excellent grades, a postbac would still help to establish a trend of recent excellent grades, which adcomms would regard positively.
BTW, you are aware that the DO application service only includes the most recent grade if you retake a class, right? So that would take out the negative effect of the Ds and F on your cGPA/sGPA since you retook them.