I don’t know if I have met anyone complaining about Ciri being the protagonist of Witcher 4. Even the most conservative people I know who are fans of the series are pumped about her being the main character because they love the story and it’s the only logical way forward. The only complaints I have heard are that in universe she’s kind of overpowered for a video game protagonist. I think people whining about this are fake fans or just agitators who don’t even play these games.