如何使用Laravel将变量从一个控制器传递到另一个控制器

To begin with the user selects a value from the dropdown list which stores the selected value in a variable called $SetNumber which is located in ControllerOne. Once the user selects from the dropdown as you cans see the form action is /Update which is used to retrieve and redirect the data to ControllerTwo

<form method="POST" action="/Update">
    @csrf 
    <select name="Match" id="Match" onchange="this.form.submit()">
        <option value="1">1</option>
        <option value="2">2</option>
        <option value="3">3</option>
    </select>
</form> 

ControllerOne contains an empty variable, which defines the variable $SetNumber. ControllerOne:

class ControllerOne extends Controller
{
    public function index()
    {
        $SetNumber = "";
    }


    public function update(Request $request)
    {
         $SetNumber = $request->Match;

         return redirect()->action('ControllerTwo@index', ['SetNumber' => $SetNumber]);
    }   
}



class ControllerTwo extends Controller
{
    public function index()
    {
        echo $SetNumber;

        return view('pages.viewpage')->with('SetNumber', $SetNumber);
    }
}

The problem is that when I try to echo $SetNumber within my controller and return it to my view , prompts me with this error:

Undefined variable: SetNumber.

how could I do this better?

i am new to laravel and web dev.