Update:
I manage to fix the issue with desktop audio not playing in windows media player.
Now I have another issue where I can't combine both desktop and mic audios so I can hear both at the same time.
Update #2
I manage to fix the issue with Obs Studio only playing one audio track.
Obs Studio only allow me to play one audio track when use windows media player for playback. A user name "koala" help me realize that the media player only allow one audio track at a time.
https://obsproject.com/forum/thread...nd-other-audio-tracks-are-much-quieter.40853/
The mixer cogwheel for audio tracks I use are:
Desktop Audio(Game Audio) - Track one
Mic Audio - Track two
But by having the tracks set up this way windows media player will only play the first track and ignore the second track and I can't here game audio AND mic audio.
What I had to do is go back to the mixer cogwheel and now it looks like:
Desktop Audio(Game Audio) - Track one and Track two
Mic Audio - Track one and Track two
All there is left to do is volume levels for both Mic and Desktop audios and I'm good to go XD.