A domain that some random person purchased wouldn’t match the contact email addresses for wherever the game is published, such as Steam Store.
If for example I released a game, even if I didn’t have a website I would still have a domain that matches that on the Steam Store, or Epic Games, etc… and the WHOIS information for that domain would have my business name and address listed, which would match the public information for the game developers of the game I’d be trying to claim ownership of. If some random person registered a similar domain and sent an ownership request to Twitch, the name, address, would be wrong and it wouldn’t match any known reliable sources that say it’s a legitimate email associated with the game.