I have a Conbee2 passthru to an unprivileged LXC (Using ZHA, not Zibee2mqtt) and on a 8.1 host.
So it should work using KVM/Qemu for you.
Although I had to chmod 777 the /dev/ttyACM0 on the host, which is less that ideal.
edit: actually I have two. One at work on a host plugged in USB2, the...