If it’s any comfort I’ve spent about a year getting away from Gmail and I can report it is in fact doable.
Finding another email service and using a domain of my own with it was the easy part. The hard part was painstakingly replacing my address everywhere I was using it with new addresses.
Way more doable than YouTube, which I don’t foresee being replicated any time soon.
You can also forward emails from your old Gmail to your new email as a bridge to ensure you don’t miss anything.
I would not forward anything from GMail to another email provider. Google is intrusive. They have no reason to know anything about my new email address. But I’m overreacting and that’s okay.
Facts. GMail took me about 4 months or so, just incrementally logging in and checking every service and subscription I have attached to GMail, logging into that account and changing the email address to my new email address. It’s a tedious task but worth it. Google is far too intrusive, imo.