Connection issues

What is the model number of the controller?

If the light is not turning on the controller upon plugging in, this would indicate that the controller itself is not syncing.

The only thing you could really double check is that the communication method on the controller through the PS4 settings is set to USB.

If this same setup worked previously with a different controller, it would rule out the possibility of the setup (keyboard/mouse) being incompatible OR not having the proper charge and sync cable required.

I’m not sure of the model number it broke so I threw it away, and the communication is usb on the ps4. It worked flawlessly with my old controller, so how would I go about getting the other controller to sync?

The syncing process would be done automatically simply by using a charge and sync cable into the controller port on the K2.

Would you be able to provide the model number of the controller you currently are having this issue with?

If it is not syncing with the controller automatically, it could be that the controller itself could be having the issue and only receiving charge from the USB.