The controller works fine over USB, but I wasn't able to confirm if it worked properly over the SNES dongle. I was using my controller on my GBA Consolizer, which has an SNES controller port. The controls were absolutely scrambled and unusable. I read online another user tried this controller on a Retron 5, and it didn't work.
This controller seems to work on the three designated devices for it (PC, Switch and SNES). However, it doesn't seem like it will work well on 3rd party systems or clone systems that support an SNES dongle.