The Apple TV box doesn’t show in Find My for anyone; that isn’t supported. Apple TV doesn’t know its own location. It doesn’t have a locking mechanism to prevent re-registering with a different user (taking over).
Find My works per Apple ID. Could it be that your MacBook is registered with a different Apple ID account? Could it be that your MacBook is signed out for iCloud services? Could it be that you MacBook doesn’t have Find My activated? Does the Find My listing change when the MacBook is online?
My Apple TV was just stolen.
You are advised to change the passwords for any account in use on that Apple TV box: for the Apple ID account(s), and also for third party services (Netflix, Prime, etc.).
Update your Apple ID password - Apple Support
How to change or reset your password - Netflix Help Center
Update your password - Amazon Customer Service