qbittorrent for desktop / server, libretorrent on android.
I mainly use a docker server setup now that works like this:
Qbittorrent via the binhex/qbittorrent docker image that also sets up a web-UI, and works well with different VPNs.
Server runs jellyfin for TV / Movies, and navidrome for music. Point these services to the correct qbittorrent download folders so that whenever you download anything, it automatically gets picked up.
On android, point qbitcontroller at your server, to easily add torrents, pause them, etc.
qbittorrent for desktop / server, libretorrent on android.
I mainly use a docker server setup now that works like this: