Generally you can do it from settings with automatic forwarding feature.

See this article for actual instructions.

Consider that:

• this means google will know your new email address
• obviously google will keep accessing your data

For the first point, Proton migration tool (from gmail) works flawlessly and doesn’t disclose your new address (plus it moves all your previous emails). I didn’t try similar tools for other vendors but I am sure they have similar options.

For me it took months to get the bulk of the services moved over, I added a label to all emails forwarded and I periodically reviewed them. It’s a perfect occasion to change password or delete the account.