https://wccftech.com/download-tvos-14-beta-3/

Apple's tvOS 14 beta 3 for Apple TV HD and 4K is now available for download. It's an over the air update for registered developers.

If you have been running the tvOS 14 beta for quite some time now and were hoping when the company would push out a new update then you are in luck today. tvOS 14 beta 3 is now available for download over the air for all registered developers, and it brings with it a handful of bug fixes and performance enhancements.