Fitness does not show up on my Apple TV.

Apple Fitness+ is currently available in six countries. Other countries will not get the Fitness app at this time.

From user reports, it appears that AirPlay is not supported for the Fitness+ content.

The Fitness app requires Apple TV (4th generation or later). Earlier models are not supported.

The Fitness app will be installed with the tvOS 14.3 update.

Due to the terms of the Apple beta program agreement, and those of the Apple Support Communities, we can provide no assistance for any Apple beta product here.

That being said, I think the issue might be elsewhere. Possibly there is a mismatch between the region of your Apple ID account (billing address) and the country where you reside.

I'm in the UK, I'm on the tvOS beta program version 14.4 and I didn't have the Fitness+ app on 14.3 and I still don't have it on 14.4. How should I proceed?