The biggest criticism I've seen to this point is not so much criticism, but surprise, I guess? Rogers' personality throughout every single MCU movie was one of a passionate super soldier who always did the right thing, often to the detriment of himself and his relationships with others. (See Civil War). So, the selfish rationalization to spend an entirely new life with Peggy, one that is void of combat, saving the world, etc., just seemed totally out of character and didn't get a lot of set up. It violates everything we know about Cap. Like, while all sorts of bad things were happening in the last 70 years, domesti-Cap just stayed... at home? Raising a family? Not helping? Why? Is that because he knew his interference would disrupt how things went?
That said, his whole life was pretty selfless. Finally choosing to be selfish feels right for Cap, in my opinion. The dude earned it, both mentally and physically. Peggy was the love of his life and he spent literally a lifetime in perpetual heartbreak.
Yeah, there's a couple ways to look at it. Can't argue with your point. But there's also the argument that he'd put in his time, done what he could and deserves a "reward."
But the main reason they went with it was to complete the Tony Stark/Steve Rogers stories by crossing them up, as it were. Tony was brash and selfish but ends up sacrificing himself to save the world. Steve was the ultimate team player but ends up doing something he always wanted for himself in the end.
Kind of a neat way to end their stories.