Accept that the internal sound card is dead to modern OSes. Disable the Pioneer driver. Connect the DDJ-S1 via USB; your computer will see it as a MIDI controller.
If the controller isn't recognized, check your USB cable and avoid using USB hubs AlphaTheta Administrative Mode: pioneer ddj s1 driver new
Your choices are stark:
Instructions on how to check your current version and apply the 1.10 update Pioneer DJ Hardware Diagram Accept that the internal sound card is dead to modern OSes
The DDJ-S1 was built for Serato ITCH . When Serato DJ Pro took over, the S1 required a specific driver/firmware handshake. pioneer ddj s1 driver new