> Can you read back the sounds you play?

No, but you also can’t do that if the user approves your app’s permission to play audio, but has the volume permanently turned down to zero.

> local storage

Give the app a temporary, space-constrained store that isn’t shared with other apps.

> bluetooth

Don’t let apps access raw bluetooth signals, but instead ask the platform to display a pairing interface (possibly with a custom stylesheet), ask the platform to call you back when a specific device is in range, etc.

> screen dimensions

Not personal data.

> input latency

Fudge the numbers even when the user grants permission.

This isn’t a war, it’s just engineering for the benefit and autonomy of the user, and not the platforms’ commercial interests.