No. When you import your existing podcast, Riverside can only import what the RSS feed exposes, which is audio, regardless of whether the podcast content contains video episodes. Riverside blocks RSS feeds that include video enclosures, and podcasts with video enclosures in the RSS feed cannot be imported.
Spotify for Creators' RSS feeds do not contain any video enclosures, so these episodes can be imported. Episodes that contain video content are converted to audio-only. After import, Spotify episodes that previously had video remain available on Spotify as audio-only. The video versions are not preserved after the RSS redirect.
Additionally, any new episodes published to listening platforms that ingest episodes via RSS, such as Spotify and Apple Podcasts, will also be audio-only after import.
If you want your podcast to appear as video on Spotify, you can claim your podcast and add a video to an existing episode on Spotify.
Video episodes can be published as video to YouTube.