Hi Garfila,
One possible reason you're prompted for a code is you have enabled parental controls or restrictions on the Apple TV. From Restrict access to content on Apple TV "To set or override restrictions, you must enter the passcode."
If that is the case, you can remove all restrictions with the following steps from that article:
"You can temporarily remove all restrictions and then add them back again later.
- Open Settings on Apple TV.
- Go to General > Restrictions, then select Restrictions.
- Enter the passcode, then set Restrictions to Off.
If you use Family Sharing, you can also use your iOS or iPadOS device to limit the content your family members can buy—including enabling Ask to Buy, which lets your kids purchase items only with parental approval. For more information, see Family Sharing on Apple TV."
Regards.