fmhy.net has german stuff, they might have what you are looking for or check the german torrent trackers https://www.sb-innovation.de/showthread.php?35824-Liste-aktueller-deutscher-Torrent-Tracker-V2

Have you checked fmhy.net? They have german content and if those dont have it you could try asking for an invite to immortous on their forum. or check the german trackers on prowlarr some might have open signups

Edit: remembered that this exists https://www.sb-innovation.de/showthread.php?35824-Liste-aktueller-deutscher-Torrent-Tracker-V2