To delete any traces of old DVR and tuners, you need to edit the Plex database directly.
Start like you would want to repair the database, as described here https://support.plex.tv/articles/repair-a-corrupted-database/
But instead of committing any of the SQL commands in the above article, only put
DELETE FROM media_provider_resources;
in there. This will empty out the table media_provider_resources.
Then close the SQL prompt and restart your server.
