We are adding a dozen audiences, will evaluation start to drag on each request?

We are scaling from two audiences to more than a dozen on the same set of slots. I am a bit worried about how it behaves when I add many audience, because each one is evaluated on the request and I do not want that to pile up latency in the App Router.

Does having many audiences meaningfully slow down evaluation per request, or is the cost basically flat? Curious how this works internally.