I'm in virtually the same situation, although qbit is running in Docker through a Gluetun/Wireguard tunnel, so that part works fine.
I really wanted to do split tunnel on my Mac to access my tracker's site (all Linux ISOs, of course) through the same tunnel, and haven't had any success.
My workaround is running LibreWolf (modded Firefox) in the same stack, through the same tunnel. It's not ideal, but at least it works.
Do update if you find a solution!