“ Punisher: One Last Kill ” is anything but. To put it plainly, Jon Bernthal ‘s anti-hero Punisher does a lot of killing in his Marvel Special Presentation. A whole lot. But layered into the over-the-top violence is a powerful character study of a PTSD-addled veteran who has lost nearly everything. Bernthal’s vengeance-fueled performance as Frank Castle has been a highlight in the MCU since he debuted a decade ago, but this time he’s pushed to his breaking point in a tense 48-minute special. To recount Bernthal’s entire MCU journey almost requires its own TV special, but here goes. He started as the Punisher in Season 2 of Netflix’s “Daredevil” TV show, which was part of a mini, pre-Disney+ Marvel universe that followed “street-level” heroes like Daredevil, Jessica Jones and Luke Cage. Like the comics, Bernthal’s Punisher was a loose-cannon, gun-toting vigilante overflowing with grief from the shocking murders of his wife and children.…