Output audio to PC built in speakers with FLX-4

I don't have that option in audio tab in Rekordbox, neither does it display the laptop with a speaker icon in the top right. I have my speakers connected via 3.5mm jack to my laptop. So I have to set the output device as speakers (realtek(R) audio) and everything works but I can't connect my headphones to the controller. I recreated the same setup on my friends laptop and there it works perfectly, i was able to set the output device to FLX-4 and connect my headphones. My laptop is Dell G15 5511 with Intel i7 11th gen and my friend has a lower quality Lenovo laptop with Intel i5 11th gen. I have tried uninstalling and reinstalling Rekordbox and uninstalling Nvidia HD audio drivers. Nothing worked.