Using iCloud mail as AppleID login?

Is it safe to use iCloud mail as login for AppleID? I created my apple account originally with gmail, but I’m slowly transitioning out of the google mail and am considering changing my Apple ID as well. But given that the mail is part of the account, is it safe to use it? Are there any guides how to best secure account while using icloud mail? Having a different mail as backup for recover? Something more?