You can try various things
1. Google Rozen Maiden and go to videos tab
2. Use qbittorent, add some anime trackers and search there or go to nyaa.si and get the magnet there (both of these require that you use a vpn so that you don't get raped by ispniggers)
3. Download stremio, add some anime addons/trackers and a real debrid or torbox api key. You will have to pay to get the api key (smth like 3 dollar a month), but its a lot faster than normal torrent and doesn't need seeders or a vpn. It works like a normal streaming app , you just need to play
Unless you are into boring niche shit that doesn't have seeders, I would stick to 1 or 2.
Here is a playlist with the series:
https://youtube.com/playlist?list=PLxZdylcczzLIyopzvP9v1E5Gl4gBpClzb