First of all, the issue is not "Solved", so I removed the "[Solved]" flair.
Second, you should not need to create your own /dev/net/tun device. It looks like you are running YAMS in an unsupported environment. Can you give more insight on how are you running YAMS? Is it bare metal? Is it a VM? VPS? LXC? What OS are you running?
I am dealing with this same issue. I created a container that has Unprivileged Container: No as the setting on my Proxmox server. I have not tried creating the tun item either.
I don't think running qbt in privileged LXC is a good idea. Is there any way to omit gluetun from the setup?
On another note, I also don't need jellyfin since i have it in another lxc but install.sh still asks me anyway, how do I omit that from the setup? should I open new issue?
To omit Gluetun you can just answer "No" to the VPN question.
Regarding the media server, it is an integral part of YAMS and we are not going to remove it from the installer. If you don't need it, feel free to manually remove it from your result docker compose file