How to set config value from Session var in Laravel

Laravel version: 7.6.

I tried to set config dynamically.

In AppServiceProvider.php, I put like this.

 public function boot()
 {
   \Config::set("variable.custom", "test"); // this worked well.
 }

But I needed to get value from Session var.

public function boot()
{
  \Session::get("test"); // returned null even used Illuminate\Support\Facades\Session.
}

So I searched about it and found one answer.

public function boot()
{
   view()->composer('*', function () {
      $test= \Session::get("test");   // this worked well.
      \Config::set("variable.custom", $test); // but this didn't work.
   }

}

Is there any solution? Can anyone help me?

via Chebli Mohamed