Symfony5: How do I set a custom method if unallowed method is used

Question

My Route is a POST route. What I want is that if someone makes a GET request then it should give my own custom JSON message instead of the below one. I even did the following but the code is crashing at the router-related file level:

MethodNotAllowedException  MethodNotAllowedHttpException
HTTP 405 Method Not Allowed
No route found for "GET http://localhost:8000/api/doSearch.json": Method Not Allowed (Allow: POST)

try {
            // Check whether the request is POST or not
            if(!$request->isMethod('POST')) {
                    $isError = true;
                    $errorString = "Method Not Allowed: Only POST requests are allowed for this resource";
                    $httpCode = 405;
            }
       } catch(MethodNotAllowedHttpException $mna) {
            $isError = true;
            $errorString = "Method Not Allowed";
       }