The availability annotations for originatingRecipient are incorrect (and need to be fixed). It is only available in OS 26 and later.

From a features point of view DASH is largely duplicative of HLS. The media team at Apple has chosen to focus their engineering time and resources on improving HLS and addressing the needs of content partners and other participants in the HLS ecosystem.

You can get help with setting up your Apple Watch at an Apple Store, or by contacting customer support.