He's an efficient 3 level scorer. I'd rather he take contested pull up jumpers than wide open threes.
But to keep it funky, I'd try to make him a playmaker or a volume dribbler.
As far as Giannis goes, he's going to get a cushion every time. He jumper is slow him shooting from 18 ft with a late contest is going to drop his percentages. He shouldn't be passing up open 3s to shoot with hand in his face. Especially off of a lazy dribble. If he's pulling up from 2 off of the drive, sure.
Honestly I think Kawhi's mindset is the same as yours. His midrange game is ridiculous.
Sad part is giannis already passes up open 3s