How do I deauthorize device on iTunes?

I have exactly the same issue the deauthorize button is not there, it says I only have one authorized computer but when I try to authorize it says I already have 5 and drives me in this mad circle with no solution.

I was able to remove a device on my MacBook Air:

• Click the Apple logo in the upper-left corner.
• Select System Settings.
• Click where it shows "Apple ID" in the upper left.
• Scroll down to "Devices" where it lists all your devices.
• Select the device to remove
• Click the "Remove from Account" button
• Click the "Remove" button to confirm.
• Close and reopen System Settings.
• Go to Apple ID
• The device is no longer listed under "Devices"

iTunes would not load on my Apple Studio. I had purchased a musical piece I wanted to play on the Studio, but it does not appear on the iCloud or via iTunes... nor on DropBox. Also, there is nonsensical confusion regarding my password which I changes and no neither the previous nor the current works on my Apple Studio as an Apple ID. I have to go on via iCloud. Very frustrating when one is simply trying to work on a project from one device to another.

Did anyone find an answer- I have exactly the same experience

I have the same problem. Apple some help would be appreciated