No he doesn't need to retire and still has PLENTY left in the tank. He's clearly a classy operator that just happens to be in a division that has world class talent in abundance. Aside from the Mendy loss (which we know the stuff behind the scenes with his father) to which he avenged, he's only lost at the very top level.... the likes of Loma and Linares are real top quality operators and Garcia is being groomed to be a future megastar. His 12 round performance against Loma (p4p #1 at the time) was no disgrace, many will argue he could've got the nod v Linares and his stock will most likely have risen stateside after chinning Garcia in that 2nd round. Still plenty of big fights out there for him.
Campbell can carry on. He could still get another chance at the belt. He will have to rebuild and needs to be fighting more regularly.
I’d move up to 140. Taylor says he’ll vacate and move up if he beats Ramirez so all them belts could be available at the end of the year. Try and get a shot at one of them in 2022 then call it a day.