Well, he could be doing some things (possibly as Nomad?)Not only that, but he also quietly sits by and lets Hydra destroy Peggy's life's work. Peggy, the woman who's supposed to be the love of his life. He let's Hydra destroy the thing she worked her entire life to build. Doesn't raise a finger to stop it.
Let's face it, Closed Timeloop Cap is a complete sociopath.
But I think I prefer the idea that there was a separate timeline where he married Peggy and they cleaned up SHIELD, kicked butt on Hydra, etc. until she died and he got old. Then he came back to the main MCU timeline a couple of months ago and laid low just in case they needed a helping hand kick-starting the time travel heist. (If that rat hadn't pushed the button on the time travel van, Cap was going to do it in a week or so.)