I signed up for a personal domain so I wouldn't have to move addresses ever again and then went with fastmail for email hosting.

Added new email to email clients, set it as the default to send from, then went down my account list in my password manager and swapped the registered email for all of the accounts I care about. Then it was just a year of replying back to people when they emailed me at gmail saying "ps. New email address as you can see"

Nothing complex, just takes time to get the message out there.