The plugin works fine, even in Nextcloud 25, probably with 26 too, as the plugin triggers ffmpg jobs that run independently of Nextcloud. The option to overwrite or not is missing in NC 25. It's nice that you can start several jobs in a row, they run in parallel.
An alternative plugin is https://apps.nextcloud.com/apps/workflow_media_converter, which allows you to automatically convert media as it is uploaded and create batch jobs to convert existing media in directory.