UTM: USB passthrough does not work in UTM, but is possible with QEMU(?)

I’m using the latest UTM 2.0.25, MacOS Big Sur on an M1 Macbook Air 2020. My guest OS is Windows XP SP3 and was installed using the configuration from the UTM Gallery. I need to use a piece of software only supported by Windows XP with a USB FTDI serial-to-usb device. I’m trying to pass USB from the host to guest by adding the following additional QEMU argument to the VM in UTM:

-usb -device usb-host,productid=0x6001,vendorid=0x0403

I have tried adding the command on one ‘line’ and also split by spaces (as it appears the generated QEMU argument list is built this way - with no luck).

When I start the VM, I get the following error:

libqemu-x86_64-softmmu.utm.dylib: -device usb-host,productid=0x6001,vendorid=0x0403: 'usb-host' is not a valid device model name

While trying to get this working, I have built a version of QEMU from source, and I can use the argument above to successfully boot the XP guest and pass the USB device through, so it is theoretically possible to support USB passthrough, although it seems UTM’s version of QEMU does not allow it? For some reason, my version of QEMU built from source is so slow and is unusable. It takes about 15 minutes to boot to desktop (!!!) and is unusably slow. UTM’s emulation is MUCH faster and is more than usable - I’d also much prefer using UTM for the GUI.

Is there any way to enable USB passthrough in UTM? Or can I rebuild UTM’s QEMU with USB passthrough support?