Comment 5 for bug 1906646

Thanks for this investigation! This issue has been discussed in multiple places, like here where a udev rule is recommended: https://github.com/systemd/systemd/issues/2891

I wonder if we could downgrade the "Requires=sys-subsystem-net-devices-XXX.device" to a "Wants=sys-subsystem-net-devices-XXX.device" and add an additional triggering condition on the sysfs path ("ConditionPathExists=|/sys/subsystem/net/devices/XXX"). AFAIU this way the wpa_supplicant unit should fail immediately, if the devices (& its sysfs path) is not there but start as soon as the dongle is plugged in.

https://systemd.network/systemd.unit.html#Conditions%20and%20Asserts

I guess this needs some experimentation to fully understand the side-effects.