Just use the controller configuration tool that is built into Steam. So far it allowed me to play any game that only allows XInput controllers with my Logitech Rumblepad 2. Here's a tutorial on how to set it up: https://www.howtogeek.com/234427/how-to-remap-buttons-on-your-steam-controller/

An older version of the x360 emulator would do it. Search for x360 v 4.10 and the System.Exception: Error calling SetupDiGetDeviceRegistryPropertyW: 122 will be solved

I managed to get three players working by plugging in only my x360 Wireless Gaming Reciever and one USB controller (actually a USB adapter for a SNES pad). Then the game finally recognised the two 360 controllers as players 1 and 2, and responded to input from the third control pad (SNES pad through USB adapter) as player 3. I was able to configure the buttons in the in-game settings menu and play. This worked without x360ce or xPadder. Perhaps my original problem was caused by having adapters for more than four controllers plugged in at once? I'm using USB adapters that are acknowledged by windows as controllers (in the directx Game Controllers control panel) even when the actual Gamecube/SNES controller isn't actually plugged into the USB adapter. So try unplugging some stuff if you have this issue.