I have this bad feeling daily that for whatever reason I loose access to my gmail. Don't think of anything shady but simply I just loose it. There is a very small chance to it but still. You can read the stories that people uploaded their family photos to google drive and the algorithm marks their kids photos CP and they loose their account. Or maybe your email is used to spam or anything similar. There is no way to talk to google support, it is an endless loop of help pages. I just can't live with this. I know billions of people do, but I cannot. My email address is registered to hundreds of websites including government and banking sites. You could literally destroy me financially or other ways by just gaining login to my gmail. Google could cause me HUGE problems by locking me out. I decided to start transitioning to an email with my own domain. I have the doimain, I have the email client setup. So what do you do with your existing stuff? Most websites dont even let you change the email. I have to take appointment in government offices to change my email. It seems like a giant task.
Have anyone took this leap?
Some e-mail providers (like Proton for example) allow you to import your e-mails and contacts from gmail - that's a start. You probably have all your passwords saved in browser/manager so you will know where to go to update them - unfortunately I don't think there's an automated way to do it, but it probably seems like more hassle than it actually is. I'd also search your mailbox for keywords like "welcome" or "account" to see if there are any other services you forgot you signed up for and haven't saved the password in browser/manager.
After all is migrated and updated, you would probably want to delete your google account but I wouldn't do that right away, just to give yourself some extra time in case you forgot about something. Log out of all google services and stop using them. Set a reminder for 1 year from now to delete the account.