I don’t think that your configuration will be working fine with multiple comments from the same user.
Here’s my solution idea
Create a query column with these filters:
ID is this row → ID
AND
Commenter email is not this row → commenter email
Create a joined list column for emails
Set the source to query column → commenter email.
Create a template column
Set the template to: $commenters, $owner
Replace:
$commenters → joinedlist
$owner → your owner lookup email column
That would make a joined list with owner email included.
Create a Unique Elements column
Set the source to the template column.
In your workflow, remove the condition and keep only one send email. Set the emails to the unique elements column.