How to disable the email notifications about regressions at all?

The email notifications are already disabled in my account:

But Sentry continues to send me emails about regressions:

You are receiving this email because you have changed the resolution status of this issue.

There is an «Unsubscribe» link in such emails, but it unsubscribes only from this particular issue.
How to disable the email notifications about regressions at all?

The “Workflow” section of the notifications setting page (from the screenshot) explains this quite clearly:

You’ll always receive notifications from issues that you’re subscribed to. You may subscribe (or unsubscribe) from individual issues on their respective pages. You’ll be automatically subscribed when participating on an issue by taking one of the actions listed above.

You’ll need to unsubscribe from the issue(s). You can search subscribed:me from the stream to figure out what issues you’re subscribed to, and then unsubscribe from them.

How to disable the email notifications about regressions at all?

There’s no way to do this at the moment, but here is an open pull request for it: https://github.com/getsentry/sentry/pull/4681