Nope, you’re reaching too far. Applications built using native frameworks will have a strong push to generally do it right, but nobody can save you from an O(n^2) loop. And even with native frameworks and engineers with access to the best resources, you can totally mess up: take macOS Catalina’s Activity Monitor app, which takes up approximately half a core updating a table view every second, which it managed to do previously with a mere fraction of the resource usage. You can’t fix everything.
> The best example I can think of off the top of my head is the Apollo app for Reddit on iOS; it is coded with 100% native platform APIs, with no slow cross-platform garbage.
Apollo is not cross-platform, but it doesn’t always use native platform widgets as I have pointed out to Christian in the past. I don’t think this has had a major performance impact, especially since they aren’t in the most computationally expensive path, but those parts probably do not interact with the platform at the layer you think they do.