Can't find "Speaker fill" on Windows 10

I just got a 5.1 surround system and when checking the 5.1 surround it plays a sound on all 5 speakers but when I play audio from anywhere (spotify, youtube, mp3,) it only plays it on the 2 front speakers (and subwoofer) so basic. I have found out then "Speaker fill" should fix this but that option isnt there for me.

I have:
Realtek version
Windows version 10.0.18363