yes, it seems that {0, 2} for aax isn’t working since quite a while: AAX instrument and supported layouts
If you only have stereo output for your instrument, overriding isBusesLayoutSupported()
like that should (hopefully) work for every plugin format and hosts :
bool isBusesLayoutSupported (const BusesLayout& layouts) const override
{
int numOutputs = layouts.getMainOutputChannelSet().size();
int numInputs = layouts.getMainInputChannelSet().size();
return (numOutputs == 2 && numInputs <= 2);
}