Since I wasn't there, I have no idea what kept happening to T.J. Warren's head. For all I know, he's just as unlucky as Danny Manning. He apparently injured his head again in Indiana
https://nba.nbcsports.com/2020/02/02/pacers-t-j-warren-head-injury/; but as you can see, that was certainly a legitimate injury--concussion. Later,
https://www.fieldhousefiles.com/p/pacers-forward-tj-warren-is-away?s=r he broke his foot. I'm not blaming him for getting injured any more than I would blame Chris Paul for having CV if he had it. (However, I do blame him for refusing to discuss whether he had it.)
Warren's "problem" is that he's uncommunicative--the second article stated that he is a "very private person," very quiet. Also "basketball is everything to Warren. He’s a gym rat, and it’s his escape. When healthy, he’ll play anywhere anytime." People probably wouldn't be so mad at him about the head injuries if he had bothered to speak up and tell fans what happened.
We've had quiet, uncommunicative Suns players for at least the last decade; players who have no interest in communicating publicly like past Suns players did. I swear, the only time I personally saw Eric Bledsoe open his mouth was to yell "son of a bitch" at Kobe Bryant. (Yes, that's hilarious in retrospect.) And more recently, it's interesting to me that for being such a pompous, "be legendary" player on the court, Devin Booker has relatively little to say off it. It happens so often that I've started to suspect it's policy, an order from above. In addition to, of course, just having quiet personalities. They make Steve Nash's players and especially Charles Barkley's group seem positively chatty. You can tell me that they aren't obligated to speak and it's true; but what can I say--I grew up with Suns players who spoke freely.
As for Warren...I still would have given him another shot, gambling on the injuries, if he hadn't wanted much money. It would have been all about the price.