Aquí hablan sobre los problemas de HDR con la app y AppleTV y Chromecast...es algo relacionado con la app, que supongo tendrán que actualizar:

https://www.flatpanelshd.com/news.ph...&id=1730196523

However, the app's dynamic range matching (SDR/HDR10) is not currently working as intended. For example, on Apple TV 4K with dynamic range matching enabled, SkyShowtime does not switch to HDR10 when HDR content starts playing. Instead, the video stream briefly signals HDR10 but remains in SDR.

When the Apple TV 4K is set to HDR10 output, with dynamic range matching enabled, the app correctly requests HDR10 content from SkyShowtime's servers, as shown in the photo. This is not optimal so an app update is required to resolve the issue.

SkyShowtime's app does not switch between SDR and HDR, or adjust frame rates, on Chromecast with Google TV either.
Vamos, lo que vengo diciendo...las apps internas de las teles...