Multiple Game Center Accounts on Apple TV

Hi CalebGrayson, We appreciate you reaching out to us. We understand that you are getting a message that your account is already in use when playing on your phone, even though you've already switched accounts on your Apple TV.

We’d like to gather additional details that may help us be in a better position to assist you.

Have you had the chance to restart your devices?

Did you use the same steps in the article below to switch accounts on your Apple TV? Access your Apple Arcade gameplay data on all of your devices

In the meantime, we recommend that you check for a software update on both your Apple TV and iPhone.

While it isn't inherently assured that an update will resolve the issue, updating to the latest software version for your device can help isolate potential software issues. 

Kindly secure a backup and update.

How to back up your iPhone, iPad, and iPod touch

Update your iPhone, iPad, or iPod touch

Update your Apple TV

Take care!

CalebGrayson,

The article previously shared mentions:

"If you share your Apple TV with someone else, switch to your account before you play your Apple Arcade game. If you still don’t see your data and you were playing on a different device, check your settings on that device."

Switching to a different account leads to the guide page here: Set up multiple users on Apple TV

Based on the articles and information it looks like the Game Center account is linked to the Apple ID/iCloud account signed in. If you aren't able to access a different account when using the set up multiple users option, reach out to Apple support directly to further assist.

Contact - Official Apple Support

Best!