Apple ID accounts cannot be registered again

I have multiple Apple devices and have registered multiple Apple IDs, all using mainland China's NetEase 163 email addresses as Apple ID names. I know that I can change the Apple ID name to a new email address in the Apple account management. However, after changing to a new email address, the previous email address should be released and I should be allowed to use the old email address to register a new Apple ID or use it for changing other Apple IDs.

I once tried to register, but the Apple system did not allow me to change it again. Why is that?

I want to clarify that I used a NetEase 163 email address to register my Apple ID in mainland China. I also tried QQ email, but I couldn't reuse it either.

Furthermore, I noticed that if the ID is registered with a U.S. email account, it can be changed multiple times.

I am a Chinese and I have a large family, so there will be more and more Apple devices. I hope that the Apple ID account, which was previously replaced, namely the email account, can be re-registered on new devices!