The app is maintained, and when a new yt-dlp version is released, a new MeTube version is automatically built with the newest yt-dlp, and uploaded to docker hub. You need to set up your system to automatically upgrade your containers with the latest image versions (I use https://containrrr.dev/watchtower/ on a regular Linux box, maybe Unraid has already such functionality built in, I don't know, I'm not an Unraid user myself), and then you'll always have the newest version of yt-dlp.