The best way to troubleshoot your setup is to test each bit by bit individually until you figure out where it’s gone wrong.
Try your qbit container without glutun. Can you download and seed a Linux iso from the same directory your current seeds are? If not, you’re probably looking at a permissions issue.
Next test your glutun container. Can you ping the tracker from the container? If not, your VPN isn’t set up correctly.
Lastly try qbit via glutun, if it doesn’t work it’s a port forwarding issue.