I probably launched some emulators at one point on a virtual machine which i guess would count as double emulation ?
that was when I had the virtual machine setup with GPU passthrough and stuff, that thing was quite insane, my computer was basically two computers at the same time (the VM was as powerful as a normal desktop since it had a whole GPU for itself, just with a fewer cpu cores)
technically if you ever played on an emulator running in the browser it is double emulation, i'm pretty sure WASM qualifies as an emulator