Deleting AWS accounts is a long, painful process, because AWS does not want to be on the hook for deleting stuff that it cannot get back. One key thing is that the email address associated with the account will be forever associated with that account. You will not be able to create a new account with that email address and you will not be able to change the email address later. So before you delete an account, change the email address to something you can consider a throwaway. Gmail and some other providers allow you to add "+anything" to your username to create a unique email that still routes to you, so I suggest you do that, using "+identity-del-201910" or something like that.
Deleting AWS accounts is a long, painful process, because AWS does not want to be on the hook for deleting stuff that it cannot get back. One key thing is that the email address associated with the account will be forever associated with that account. You will not be able to create a new account with that email address and you will not be able to change the email address later. So before you delete an account, change the email address to something you can consider a throwaway. Gmail and some other providers allow you to add "+anything" to your username to create a unique email that still routes to you, so I suggest you do that, using "+identity-del-201910" or something like that.