You can pull in emails from your old gmail via imap into your new account. Within roughly 5 years from 2010 to 2015 I switched over from an iCloud account and g

You can pull in emails from your old gmail via imap into your new account. Within roughly 5 years from 2010 to 2015 I switched over from an iCloud account and gmail to a custom domain and server. In that time, almost all logins were transferred. 5 years is a long time, though.