I do JFK-GRU-SDU a lot. GOL is a pretty relaxed airline and the cash ticket between GRU-SDU/GIG is usually pretty cheap. I wouldn’t worry about misconnect. Also I am surprised the original poster couldn’t get a Y class award seat on GOL added to JFk-GRU. It rarely shows up on delta.com, but agents can book it (and there is usually availability as there are so many flights)