Don’t feel like you have to race. It took about a year to shift e-mail addresses last time I did it. Keep the old one as a harvesting point until you move over what you want. Then just leave the old one around to use up space on Google’s servers if you really want to softly be a dick. (They eventually close them after some period of inactivity.)
Basic steps for a slightly more thorough method that also preserves old e-mail:
Do a GDPR/Google data dump of your gmail to mbox file(s).
Turn off all mail rules on Gmail so everything just comes to the inbox.
You can forward to your new address if you want to, or, just let email collect in the old account and switch addresses from time to time as you use various services.
After a time, delete the account if you so choose, or leave it dormant until Google deletes it.
Don’t feel like you have to race. It took about a year to shift e-mail addresses last time I did it. Keep the old one as a harvesting point until you move over what you want. Then just leave the old one around to use up space on Google’s servers if you really want to softly be a dick. (They eventually close them after some period of inactivity.)
Basic steps for a slightly more thorough method that also preserves old e-mail: