Except you did when you said that “any engagement, even non-commercial, has the effect of promoting the brand.”

That is assigning blame onto the consumer, as you blame them for the effect of their action. Her brand is being promoted regardless, because the industry that is “advertising” exists. Additionally, the effect from people consuming her media is negligible, as even if you boycott and spend that money elsewhere it is still just being funneled to some other bigoted owning class fat-cat doing the same shit because that is how the system is designed. It just means that she, specifically, won’t be getting the money, while just denying yourself something that you wanted, assuming you actually liked the franchise to begin with.

So the best thing to do is encourage people to find ways to bypass these systemic barriers without needing to sacrifice their own desires so that the system which enables these bigots loses its power to restrict our access to the things we need and desire unless we enable them.