Apple Podcasts offers Channels, content hosted on Apple Podcast Connect and available on Apple Podcasts alongside public podcasts. This supports free and paid versions of the same episodes alongside one another.
Please read the process in Apple's documentation here:
Under Step 4, two options are provided for linking your paid and free audio together. Omny supports the second option.
NOTE: Option one is not possible in Omny Studio as episode GUIDs are set automatically and cannot be user-modified.
To set your episodes Season and Episode Number and Episode Type, please follow this guide:
For any questions, please contact support.