Probably the last season of Giannis in a Bucks jersey if they will come up again short this season. 
https://www.jsonline.com/story/sports/nba/bucks/2020/12/15/giannis-antetokounmpo-signs-supermax-milwaukee-bucks/3843891001/
He will signed a supermax deal with the Bucks, I doubt if he will be traded even if the team will fall short this season.
The coaching staff has to be replace I guess, I think that's the first thing they have to do, just like what they did with the Clippers.
Players are not usually the problem, it's the coaching IMO.
Let's wait for Giannis decision, I'm not sure why he is still not signing that dotted line though. But he has a super max contract on the table, and just waiting for the final day before officially accepting it. But then again, Giannis should really bring the Bucks to the finals, that's all great players do. Maybe he just needed another superstar in the team.
But if he failed again this year, I think the coach head are going to be roll and then maybe we will see another set of trades to acquire another superstar to help Giannis bring Bucks the championship.
https://www.espn.com/nba/story/_/id/30526147/giannis-antetokounmpo-milwaukee-bucks-reach-five-year-228m-supermax-extension
Well there it is. Seems as though the cards are in place now that he is committed Bucks have to be all in. These next coue years are crucial for their franchise since now they gave up a ton of picks.
They bet so much for Giannis that's why their future mostly depends on the development of Giannis, however if they will be tired and still failing to get in the NBA Finals, I think they can still use Giannis to acquire a another superstar to lead the team and that is by trading him, they just have to ensure that Giannis will remain healthy so his value will not go down.