I just read some of the comics and was pretty shocked that amber and rex were actually white in the comics. In almost every piece of media I’ve seen where characters get race swapped people are mad so is that the case with invincible?
Rex just has a darker complexion and dark hair… he’s just meant to resemble Jason Mantzoukas more. In the comic he was just more fair in appearance.
Amber just isn’t that important of a character, nobody is attached to a particular image of her so most people don’t really care if it’s changed. If they made Atom Eve look different would probably be a different matter.
Personally I’m picky on details so the fact that Monster Girl has dark brown instead of light brown hair and that half the characters have imo ugly bangs bothers me way more than anyone’s skin tone changing.
Biggest negative change is the general lack of space tiddies