How to pass data through scenes?

Hello

i have 2 scenes, Settings scene and a Gameplay scene.

in setting scene there is a sound option(on/off)

so if sound=off no sound in gameplay and viceversa

here is the sound script, the name of the script is Soundonoff

 public int soundset;
     
     void OnMouseDown()
 
     {
         if (gameObject.name == "Off")
                         
         soundset=0;
 
         else if (gameObject.name == "On")
 
         soundset=1;
     
     }

and my gameplay script (simple version)

 public Soundonoff ss;
 
 
 if (ss.soundset==0)
 
 //sound is off
 
 else if(ss.soundset==1)
 
 //sound is on

but i keep getting the error

"Object reference not set to an instance of an objet"

is there anyway to pass data through scenes?

PS:i already know about static and playerprefs so are these the only ways to pass data through scenes?