Moving purchases from one Apple Account to another

I have operated an Apple Account for a long time using an email address that uses a personal domain (e.g. fred@xyz.com.au) that I now need to shutdown.

I would like to set up a new Apple Account using a generic domain (e.g. fred@icloud.com) and transfer purchases from the existing account to the new one.

I have been told that this is not possible but I thought that I would check here.

Also, if what I was told is true and I cannot transfer them, I was advised to simply create a new account and sign into it on my devices. Thereby making purchases done through the older and newer accounts accessible to the devices. What happens in the case of the older account when the email stops working when the domain is not renewed. Can I set the email address for the older Apple Account to be fred@icloud.com, replacing fred@xyz.com.au?

I hope this makes sense.