*This review will contain minor spoilers from “The Falcon & The Winter Soldier,” but those sections will be marked.* “The legacy of that shield is complicated,” Sam Wilson (Anthony Mackie) says warily, his inner turmoil churning away, early on in “The Falcon And The Winter Soldier,” Disney+’s new Marvel Studios limited series. Captain America’s shield—bequeathed to him at the end of “Avengers: Endgame” by a-now-aged Steve Rogers—should be a gift.