Well, it's just steam mirror from my Laptop but yeah, It was a unique experience. I try to play in VR PC before but this it better.
You need
1. PC or Laptop with better WIFI connect
2. Your Samsung and use in GEAR VR [I use S10+]
3. Buy Virtual Desktop on Oculus Store [But if you have Oculus Quest or GO, it's can use too]
4. connect your PC and your Samsung mobile in VR mode
5. Connect your keyborad and mouse - ENJOY!
Link - https://www.vrdesktop.net/
Basiclly, it's use from Virtual Desktop App in my S10+ with GEAR VR, But it's better than Samsung Phone cast, that app can't work anymore
Of couse, play in VR isn't good choice compare play on PC but if I want to fall down and play a sample or watch Story, It's best way for me.