Hi,
A similar issue has been solved - thanks for the tips to sintei (https://forum.proxmox.com/threads/usb-pass-through-in-lxc-container.73742/#post-329417).
Cgroup 189 and /dev/bus/.. useless here, instead, you need the following in lxc.conf:
lxc.cgroup.devices.allow: c 180:* rwm...