USB custom hid vs stm32 hid and sending MIDI over USB

[hashtala]

So I generated Custom HID project with Cube

Changed descriptor and it worked as intended

Then I generated "generic" HID offered by Cube

Changed its report but it didn't work, PC said that there was problem with a descriptor

I did that because intially what I wanted is that I would generate Audio Class device code, change descriptor to MIDI and use it, but as I can see it is not possible to change descriptor unless it is custom ?

So is there any way around this ? or do I use custom HID and then change descriptor to MIDI ?