The X factor on offense for the Bucks (and perhaps the series) is Giannis' passing. I've noticed in the last few games he has been very good at recognizing when he has the ball when Phoenix is "building a wall" to stop him, and he makes a quick decision to get the ball out of his hands and swinging in to another player, who can attack a defense that has already begun its rotation to stop Giannis from getting to the rim. Not all of these plays have led to assists (he had 8 last night and 6 in Game 3) but it gets the ball moving and leads to generally good looks for his teammates. He's also done a good job finding guys like Lopez in the dunker spot when he does get closer to the basket and players rotate over to wall him off.
You really can't be one-dimensional and win an NBA title, no matter how good you are at one thing, NBA defenses are good enough over the course of a series to stop you from just doing that one thing over and over again. I think Giannis unlocking more playmaking skills is a key way to differentiate the Milwaukee offense and create a more sustainable way to score, while also instilling confidence in his teammates and role players. He isn't LeBron or Luka, but he has shown to be smart enough with his decision-making to punish teams who try and build a wall. I've selected some nice plays below:
In this one, he brings the ball up and catches Crowder cheating to try and get ready to cover for Craig if Giannis blows by him; Giannis quickly moves the ball to Middleton, who is able to attack the close-out and get a layup.
https://www.nba.com/stats/events/?GameEventID=164&GameID=0042000404&Season=2020-21&flag=1&title=Middleton 2' Driving Layup (9 PTS) (Antetokounmpo 2 AST)&sct=plot
A different look here; Connaughton sets a screen and Ayton is very concerned about Giannis so he doesn't move a muscle as Paul tries to fight through the screen. Connaughton leaks out and Giannis quickly finds him for a three before Paul can scramble back:
https://www.nba.com/stats/events/?GameEventID=433&GameID=0042000404&Season=2020-21&flag=1&title=Connaughton 26' 3PT Jump Shot (3 PTS) (Antetokounmpo 6 AST)&sct=plot
In transition, Giannis gets the ball and Ayton and Crowder immediately move to the paint to the protect the rim, and Giannis recongizes the rotation almost before it even begins, and finds Connaughton for a wide open three:
https://www.nba.com/stats/events/?GameEventID=612&GameID=0042000404&Season=2020-21&flag=1&title=Connaughton 24' 3PT Running Jump Shot (11 PTS) (Antetokounmpo 8 AST)&sct=plot
Finally, here is getting into the paint; Ayton once again sticks to him like glue and ignores the fact that Lopez has already gotten behind him. Giannis finds Lopez in the dunker spot for an easy two:
https://www.nba.com/stats/events/?GameEventID=21&GameID=0042000403&Season=2020-21&flag=1&title=Lopez 2' Reverse Layup (2 PTS) (Antetokounmpo 2 AST)&sct=plot