Enabling XDebug has been added to the DevKinsta UI as of version 2.9.0. After reviewing the article you shared, it seems that you can skip steps A and B and simply enable XDebug in the DevKinsta UI. Then, proceed directly to step C to configure PHPStorm.
Although, It is always recommended to make a backup of your data before making any changes.
I have also forwarded your feedback to our developers, and hopefully, we can release an official help page for configuring PHPStorm. 