Image: Android Authority
You might be able to use a temporary email with your Gmail soon. At least, references to the feature were spotted in the Gmail Android app's apk file. Google calls it "Shielded Email." The idea is you get a temporary email address you can give out to third parties instead of using your actual email. And when you receive emails through this address, they get forwarded to your regular inbox. If you want to kill the account and not receive emails through it, you can easily do so without dealing with unsubscribing or other tedious processes.
From the screenshot shared by Android Authority, it seems there might be options to have more than one Shielded Email. However, it's unclear if Google will roll out this feature. We will keep our eyes out for any updates.