Open Gmail and sign in to your account
Click your profile picture in the top-right corner
Select Manage your Google Account
Go to Data & privacy
Scroll to Data from apps and services you use
Click Delete a Google service
Sign in again if prompted
Find Gmail and click the trash icon
Enter an alternate email address for Google services
Check the confirmation email sent to that address
Open the email and follow the deletion link
Confirm the deletion of Gmail
Keep your Google Account if you want to use other Google services
Back up any important emails before deleting Gmail
Update your email address on other accounts before deletion