You can definitely delete both Editor and Published Comments. Here are a few things to consider...
Deleting Comments in the Editor
Click on the Comment you'd like to delete and then click the Three Dots and choose Delete
This will delete an individual comment in the thread but not the whole thread.
Worth nothing that your Editor Comments will not be visible on the Published Site so you don't NEED to delete them but you can if you'd like
Deleting Published Comments
Click on the Comment you'd like to delete and then click the Three Dots and choose Delete
If you don't want to get rid of the comment but just want to remove it from viewed, you can also click the ✔️ to mark the comment as resolved and hide it from view
