Luka didn't get along with Porzingis and seems to have trouble getting along with a bunch of people. Those rumblings have been out there for a while from reputable sources. He has had times where he was out of shape and had poor body language on the court along with not playing defense.I don’t know too much about nba but haven’t gotten the impression Luka was immature or drama queen.
Grants got a big personality. Also has a big brain, heart, and drive. I would suspect maybe his “rubbing people the wrong way” has more to do with the leaderships opinion of him than the players. Not a good look for Dallas’ future if they couldn’t mesh with a team player like Grant.