https://wccftech.com/download-watchos-8-and-tvos-15-beta-4-right-now/

You can now download and install watchOS 8 and tvOS 15 beta 4 on your compatible devices right away.

Apple is working round the clock to make its upcoming software as stable as possible. Today, we have new (yet more refined) versions of the software to play with - watchOS 8 beta 4 and tvOS 15 beta 4. Keeping tvOS 15 aside for a minute, we expect the new Apple Watch software to be more stable than before and hopefully features lesser crashes and offers better battery life.