What about adding
killall -9 AudioComponentRegistrar
in the AudioUnit copy phase ?
Otherwise you cannot test your AU straight away.
Maybe doing it only in the case of the .component not existing in the folder previous to the copy.
Moreover in the plist type is wrong, it uses kAudioUnitType_Effect instead of aufx
Otherwise it’s not detected in auval
At least this is what should be done according to https://github.com/WeAreROLI/JUCE/tree/juce6/examples/CMake
so either update the doc (and mentioning we should use single quote) or it should be converted by the cmake