The following screenshots from other WiiM users seem to imply otherwise:
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Source link #1)
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Source link #2)
To my knowledge any UAC1-compliant (USB Audio class 1 device) USB microphone should work in Android and therefore be recognized by recent versions of the WiiM Home app.
One issue can be if the specific phone model USB port can't produce sufficient power for the specific microphone - in which case you'd need to use a USB hub with external power between the phone and the mic.