@dustbro The Standalone App will have only a Stereo Output and the Multichannel Plugin have 8 stereo outputs by default (16 mono channels) if you want more than 8 stereo outputs you need to edit the NUM_MAX_CHANNELS in Macros.h and use the flag "HISE_NUM_PLUGIN_CHANNELS=16".
But what I do is creating a routing matrix trough scripting via combo boxes with the "addConnection" Function using a Typed Routing Matrix Script Reference, in the Standalone you don't hear any changes but in the exported plugin the function will work if you use the Flag.