I Receive Notifications When Records Are Edited Even Though I Do Not Choose to Receive Them

It is probably because you are specified as an assignee for process management.

In the app with process management enabled, notifications will be automatically sent to the users who are specified as assignees when the records are edited.
This notification setting cannot be disabled.

It is also explained in "When a record is updated" section in the following page.
When and to Whom Notifications Are Sent