Here's the short of it: The Rock wanted to play Black Adam for ages and DC was all about it. However, the production of the movie took many twists and turns and Dwayne implanted many of his own people on the project, he was basically allowed to take near creative control of the entire thing. The budget ended up going completely out of control, some say it ballooned to over $250M.
So, he really needed it to be a big hit and it wasn't. It was a pretty big flop considering how much the budget was. The Rock also snubbed them on being in the Shazam universe until all of this was over with. Black Adam is the major antagonist to Shazam.
Meanwhile, Warner Bros. merged with Discovery and has a bunch of new executives.
The Rock attempted a power play against WB/Discovery and wanted them to greenlight a sequel with him and Henry Cavill returning as Superman.
The new executives told The Rock to get the hell out of here with that and James Gunn (coming over from Marvel who is now the new President of DC) announced a slate of new DC movies and none of them are going to feature Dwayne.
The Rock found out a lot about trying to make power plays vs. multi-billion dollar corporations. Very few in Hollywood would have gotten away with it, Actually I don't think anyone would.
He is now trying to rebuild his image.
