To be fair, that design is a pretty basic one. Like extremely basic. Sure it's cleaned up and modernized but trying to say it was stolen is a reach. Elon does still have the Midas Touch where everything turns to gold, in which he subsequently murders everything he touches and makes even gold worthless.
This is like the discussion about how others were copying Apples corners, they are fucking round corners.
There is only so much you can design about an X, so no matter how they would design it, someone made that.
You can find countless issues with Musk, but that's just sad and desperate.