Thank you for reading my post!

Every API call takes time, that is why there's the cache mechanism - it reduced API calls.

I assume AWS CloudWAtch Evidently uses the same API calls that AWS AppConfig provides. There's no magic here.

As for LaunchDarkly, I havent used it, it's a far more feature rich and complicated solution and you should check if it addresses your needs.

This post describes a barebones, no UI, developer oriented feature flags solution.