Alexey Naumov in Performance Battle: AnyView vs Group:

I cannot say there is a clear leader among AnyView and ConditionalView, but the myth about negative AnyView performance implication is BUSTED.

I take most of what I see on Twitter with a grain of salt, especially when it’s technical advice that’s not backed by examples or reproducible benchmarks. In the case of SwiftUI, there is no shortage of guesswork and hearsay given how under-documented the framework is. And while I appreciate the openness, the occasional tweet from members of the core team is not enough to fill the knowledge gap.

Luckily, there is always an industrious soul in the community that rises up to the task of winnowing the chaff from the grains.