I went to Transmission years and years ago because it's just simple. It has all the options if you need them, but no HUUUGE interface with RSS feeds, 10001 stats about your download, categories, tags, etc etc etc.

Transmission is just a small, floating window with your downloads. Click for more. It fits in the macOS vibe. But I'm a person that fully adopted the original macOS "way of working" - kicked the full-screen habit I had in windows and never felt better.

Can I ask, why would you go FROM Transmission to qBittorrent?