Personally, I think that should depend on her actions on/off set as well. Like is she just saying "nah I don't think people should be vaccinated if they don't want to. You know my cousin in Trini got this friend...." or is she actively on set saying "I'm not getting vaccinated, I'm not wearing a mask. Wake up sheeple!".
If she's putting other cast and crew members at risk of getting sick (aka shutting down production) on top of the bad press she's bringing by being anti vax then I wouldn't be surprised if Marvel take the cost of reshoots on the chin just to get her out of there. Remember, even if she's the main character and the movie was literally called BP2: Shuri's Takeover, not every scene is a massive closeup of Letitica Wright's face. There's all those CGI shots, reaction shots from other characters, action shots with stunt doubles, etc.
I mean at the very least I'm sure Marvel's pissed off that every time Shuri is trending on twitter is because Letiticia Wright is doing her best Nicki Minaj impression.