That may be true, but I think he might have a case...

The lawsuit said that Ackerman sent a pre-publication copy of the book to the Tetris Company earlier that year. He said the company refused to license its intellectual property for projects related to his book, dissuading producers who were interested in adapting it, and sent him a "strongly worded cease and desist letter."

So he made the book, presented it to Tetris, they rejected the idea, threatened him to sue if he did his own thing, rejected other producers, then I guess partnered with Apple and made it as if it was their idea.

Are there fictional elements or speculations in Ackerman's book that were translated to the Apple movie?

I think so, I think it's more a thematic kind of thing, not the history per se. But I haven't watched the movie or read the book, so this is just my point if view from what the article says.

No idea if it works like that or if he would have a case as I'm not a lawyer, or writer, or producer, so take what I said with a pinch of salt.