SharePlay should work internationally for many streaming services, but those may have their own international restrictions, exceptions, and caveats.
➔ Note that SharePlay only syncs, but doesn’t bring you content that you wouldn’t have access to on your own. It is not free content sharing; not a way to stream US-only content in Germany, or vise versa. Verify that for the intended content.
Use SharePlay to watch movies and TV shows together on your Apple TV - Apple Support.
Use SharePlay to watch, listen, and play together in FaceTime on iPhone - Apple Support.
For iPhone, iPad, iPod Touch, and Apple TV box, you would need OS version 15.1 or later. For Mac, you would need macOS Monterey 12.1 or later. That may exclude some older devices.
Else contact Apple for support and service - Apple Support.