Just passthrough the ports instead of the devices. It works much better and iam passtrough BT and Zigbee in parallel without any issue. PS: iam using and recommend zigbee2mqtt instead of ZHA. (Depending on the chipset). More stable and way better interface.
Technically no real change but some devices have multiple IDs (the sonoff stick has a second bootloader, too) so you could upgrade the stick from the guest, too because you passthrough the whole USB port Independent from the device ID attached to it.