The most straight-forward way of doing this may be to start with the transfer of the domain. Once you do that, the new owner will be able to make changes to the nameservers. If they setup a new account, they’ll have two nameservers assigned to them and they’ll be able to instruct the domain registrar to make the change. An added benefit to them would be if you were to export the DNS records and share those with them. On the DNS app of the cloudflare dashboard:
That might help get them started, although they may still need to make changes for their need. Also, there is another party involved, your hosting provider. The new owner will need to make a decision to continue or change hosts and that may affect the origin IP.
Your account is linked to your email address so I don’t know that a transfer of the account itself is an option.