Trouble entering recently changed Apple ID password into Apple TV HD

Here is more accurate/​complete information:

When you try to sign out for iCloud services, you find that it is grayed out. The explanation for this option is listed on the left, below the image: “To change the iCloud account of the Default User, first remove user from the Apple TV, then add a new Default User.”

* I’ve thought about “removing user” with all the data, but hesitant to take that step so far.

No worries. The account data is retained, only to be removed from this device temporarily.

Afterwards, you can sign in again, e.g. with assistance from another Apple device (iPhone or iPad), and all will be restored. [Just tested for my own Apple TV box.] Reminder: If you had a secondary account on the Apple TV box, then that would still be active (since the removal); you would have to additionally switch back to the ‘new’ Default User.

Try signing out for the account options (iCloud, Store, Game Center) first, then sign in again for each of those.

Understood. In that case, I would reset the box and start over. Important: use an iOS 16+ phone for all setup actions that require an iPhone.

… but “sign out” is grayed out for the iCloud option and won’t recognize button press.

Seems like iCloud is in use for something then. HomeKit perhaps? Is the Photos app open?

You can ignore it - it’s a gimmick that requires iOS 16 or later, but otherwise has no impact (other than to cause needless tension). I’ve ignored it without any issue (I don’t use HomeKit).