I know what you mean and would like to be able to reorganise folders etc but in practice the example you describe doesn’t need sub folders.
Simple enter the MBritt main folder then search for whichever amp type you want the new list contains only the amps you want so you can now do any sorting you need on the search results only. Unfortunately there is a bug just now which is screwing this up but they are aware of this and will fix it again soon.