I'm so sick and fucking tired of Qbittorrent.
Is there any torrent client allowing me to download something one at a time and if it drops down to 200 mb/s, it'll pause and resume something else which can be downloaded?
Don't use any clients based on libtorrent libraries. These issues are likely related to libtorrent, not qBittorrent itself.
Tixati, Transmission and uTorrent are a few non-libtorrent clients out there, but you may want to do some research for a more comprehensive list so you can compare them.
Deluge is based on libtorrent. It has the same issues.