but fuck me, I don’t feel like going through the process of making sure I have everyone my new email, change all my accounts, etc, so I’m taking my time sunsetting it

Set up your gmail to have a mail forwarding rule, so that any message it receives gets forwarded to your new address. After switching over your more major things, all you need to do is keep an eye out for things that have been forwarded from your old gmail, and switch them over when you notice one. Eventually, very little will be going through your gmail anymore. Even then, it's not a terrible idea to leave it open and still forwarding, just in case someone important tries contacting you there years later. But with this forwarding strategy, you can pretty quickly get it so that 90% of your messages don't go through gmail anymore. While cutting google out of your life completely would be ideal, reducing usage and reducing what they have access to is still a good thing.