Can Family Sharing be set up without an Apple Device? I have an AppleID and an Apple TV account, but no Apple device.

Set up Family Sharing in the Apple TV app - Apple Support

"Activate Family Sharing

You can’t activate Family Sharing directly in the Apple TV app. You must set up Family Sharing on a Mac, iOS, or iPadOS device.

To activate Family Sharing in the Apple TV app TV app, follow the steps in the Apple Support article Set up Family Sharing [ Set up Family Sharing - Apple Support ]."

And:

To learn how to set up Family Sharing, read this support article --> Set up Family Sharing - Apple Support

- Only lists doing this on an iPhone, iPad, iPod touch and Mac.

Just in case you are one of those people who actually read Apple's documentation (which I am guessing some people reviewing this may not) you may wish to note this somewhat confusing statement from: Use Family Sharing with Apple Music on Android - Apple Support

which says:

"How to start and manage your own family group

When you get an Apple Music family subscription, you can start and manage a family group to share your subscription."