This is sweet, this exact same idea has been kicking around my head for awhile but I’ve never taken the initiative.
I did write a script (powershell lol), that uses yt-dlp to download all your subscription videos as they come in and sends a notification. Could easily be modified to work on linux and use ntfy or another notification service. ALso no need to scrape your subscriptions as it stays in sync with your currently subscribed channels.