I use this one with my Windows 10 PC connected to a Cobalt Flux pad and it works perfectly - https://www.amazon.com/gp/product/B00FBM3F72
If the adapter works with other pads, then it's the pad, else it's most likely the adapter or the driver for it.
I have success with this adapter on Windows and the Stepmania Axis Fix enabled in settings: https://smile.amazon.com/dp/B00FBM3F72
I was able to get my RedOctane soft PS2 pad working on my Windows 10 PC (no drivers required, plug and play with newest Stepmania) with this adapter: https://smile.amazon.com/dp/B00FBM3F72
a adapter of ps2 like this: https://www.amazon.com/-/es/OSTENT-Computer-Controller-Adapter-Converter-Compatible/dp/B00FBM3F72
Hey, if you're still looking for a PS1/2 to USB adapter, I'd recommend this. You'll need to install drivers from their website so that it doesn't input the arrows as a joystick.
https://smile.amazon.com/dp/B00FBM3F72
This adapter worked for my old PS2 RedOctane soft DDR pad on Windows, just need to check the "Axis Fix" box in the Stepmania settings.
Also, make sure it shows like this in the Game Controller settings within Windows: https://ibb.co/0QtvbkR
I was able to get my RedOctane soft PS2 pad working on my Windows 10 PC (no drivers required) with this adapter: https://smile.amazon.com/dp/B00FBM3F72