Slsk
via nic+ 👍
In general, I recommend adding Jackett to qbittorrent. It works great and is much better than the standard search add-ons.
For this specific request, AudioBook Bay has a 30 lesson Dutch section (in a large general pack) and is dated 2022 (also available via Jackett in qbittorrent).
Not a site, but Nicotine+ is where you can drop anchor.