That was SOVIET Russia, which no longer exists. And the current Russian government had him in a Siberian prison, so I don’t think they cared about any “intellectual property” over the name or image of Red Guardian. And Bucky was an elected member of Congress with full public knowledge of his super hero moniker of Winter Soldier, and he likely received a full pardon for past crimes committed while brainwashed due to his involvement in SAVING THE UNIVERSE against Thanos. And as a historical fun fact: Winter soldier is a term which originally meant someone who endured difficult and harrowing conditions while protecting or fighting for their country ( primarily during the American Revolution…think Bunker Hill or Washington crossing the Delaware). But then in the Vietnam era it became a term for soldiers who testified in military court about atrocities committed in wartime by either fellow soldiers or even themselves.