Go to your plugin editor and look for line 41 in the theme enabler plugin and change it to: return is_singular(‘web-story’); // enter your if condition here. Reference: https://codex.wordpress.org/Conditional_Tags
Now go to Oxygen > Theme Enabler and select the second option “Use Oxygen for most pages but use theme on the select views defined by the condition(s) in plugin file”
After that go to your Oxygen main template and change the settings to:
In the “Singular” tab put a checkmark on “Pages”
In the “Other” tab put a check mark on “Front Page” and make sure to leave “Catch All” unchecked.
At the end don’t forget to crawl your new web story in Google Search Console and request indexing. Have fun!