As per release notes for tvOS 17.3, there are no new Apple TV features in this update. But don't skip it—you're recommended to install even bug-fix updates.
tvOS 17.3 release notes: Bug fixes and performance improvements
tvOS 17.3
As per release notes for tvOS 17.3, there are no new Apple TV features in this update. But don't skip it—you're recommended to install even bug-fix updates.