MacRumors published a story that Apple has released the third beta of tvOS 17.4 to registered developers.
Apple Seeds Third Beta of tvOS 17.4 to Developers
Apple today seeded the third beta of an upcoming tvOS 17.4 update to developers for testing purposes, with the beta coming one week after the release of the second tvOS 17.4 beta.
Registered developers are able to download the tvOS 17.4 update by opting in to the beta through the Settings app on the Apple TV. A registered developer account is required.