I believe with the Witcher is was a very disappointing situation for him
In what sense? I've heard a lot of weird evidence-free "theories" (which is naming them generously!) from mostly* alt-right adjacent types or full on "anti-woke" loons which claim he was in conflict with the team on The Witcher show, but literally everything he and everyone he actually worked with on The Witcher has said suggests otherwise, as far as I'm aware. This whole conflict seems to be completely made-up nonsense, multiple layers of what is essentially fanfic.
It seems to me like he left because the show wasn't as successful as he hoped, which, frankly, was predictable, because The Witcher stories are not... very compelling... nor really have the mass appeal of something like LotR or GoT (the games tell the stories better than books do). They actually did a better job presenting the material than I expected, albeit the budget was clearly fairly constrained forcing a lot of chopping down of stuff. Indeed I rather wonder if Netflix suggested cutting the budget further - historically they've been very keen** to do this on S2s and later of shows, even if it makes absolutely no sense to why people watch the show (which may well be in part because it looks beautiful/pro), and perhaps to the point where it potentially impinged on what Cavill was being paid - and he was probably being paid a lot less than he would have been for a movie role taking a similar amount of time/effort. Certainly the actor they replaced him with is er... fairly cheap.
Whereas a DCU Superman film would have likely had him being paid $20m+ (as Variety believes he was for his fairly brief appearance in Justice League).
So I don't think we need to be upset for him about that. It's unfortunate maybe but he clearly made a choice to leave a show that starred him to earn tens of millions in a movie that didn't end up getting made based, according to Variety, on a single verbal agreement which he may not even have directly been party to! What's interesting to me is that at the time he jumped ship, there were already publicly-surfacing rumours that the DCU was about to make "big changes", so actually Hollywood insiders would have known for at least weeks, maybe longer. As such, I was going to say "If I were him, I'd have fired my agent/manager for being incompetent!" but I then checked and that's exactly what he did!
His manager is Dwayne's ex-wife so they must have thought it was inevitable.
Yeah no-one should be listening to the Rock and it got Dany Garcia fired as Cavill's manager. The Rock absolutely is drinking his own Koolaid (hopefully not from the same bottle he admitted to peeing in on set!) when it comes to what's happening in Hollywood, to the point where he got into angry denials about Black Adam's poor box office showing, basically implying people were making it up, before having to admit actually it didn't make as much money as hoped. I feel like he's on a rather unfortunate path - denying reality is never a good start. His whole schtick of being a huge wrestler dude who can kinda act has essentially been taken by Dave Bautista and John Cena, except both of them actually can act and have way more charisma and are younger than him, so I think he's a bit pissed off generally.
Cavill's main issue I think is actually that he
can act, but keeps getting put in roles where they don't want him to act much (c.f The Witcher, whose whole deal is he's pretty stony-faced and faux-emotionless), or the director isn't good at eliciting good performances. Like, look at The Man from UNCLE movie - Cavill gave an astonishing performance as Napoleon Solo, absolutely riding the line between impression and inspired with his accent/diction/body-face language and so on. But the director was Guy Ritchie, who has extracted tremendous performances from all sorts of people, not Snyder, where good performances seem to be despite him rather than because of him.
Unfortunately one suspects if he's playing a Space Marine or similar it'll be another case of them not really wanting much acting, just a lot of stoicism and shouting. But who knows?
* = It seems like the original story was entirely made up by a person who disliked Cavill and was trying to make up that he was a bad guy (which he may or may not be, but there isn't any evidence for him being anything worse than a yet another male actor who dates people twenty years+ younger than him, looking at you Leo DiCaprio!), but alt-right people pounced on it to sort of uno-reverse'd the fictional conflict into him being a "true fan" and "hero" fighting for the "real Witcher".
* = For the most insane example compare S1 and S2 of Altered Carbon. Despite getting a possibly more expensive star, S2's overall budget has clearly plunged hugely from the $150m of S1 to the point where it looks like, dare I say it "2000s era Canadian sci-fi"!
I have not met a 40k player that didn't like it. Everybody in my 40k circle liked it.
Sure, but what does that mean? A lot of people are so keen for any kind of 40K representation that they say they think pretty much any high-end 40K CGI is amazing. That's been true for a very long time - countless slightly dodgy fan animations and videogame intro videos have been hailed as "AMAZING" by 40K fans even when they were pretty crummy. The bit with the daemon was good, but the rest was meh.