Returning HandlerResponse from ExtensionMethod

Question

I'm refactoring my commandhandlers to return responses through extension methods (or possible delegates). Trying to move from:

var object = _repo.GetObjectById(id);
if (object == null) return new Response();

to:

object.ReturnIfNull();

by using:

public static Response ReturnIfNull<T>(this T root)
    {
        if (root == null)
        {
           return new Response()
            {
                Errors = new List<ResponseError>
                {
                    new()
                    {
                        ErrorCode = ErrorCode.Unknown.ToString(),
                        Field = $"{typeof(T)}Id"
                    }
                }
            };
        }          

        return null;
    }

Ofcourse this method atm return null or a Response to the handler. In that case, I should catch the result in the handler, and do another null-check before passing Response back to controller. My goals is to do this in a one-liner. Is this possible? So when ReturnIfNull() finds root to be null, the handlers returns the results from ReturnIfNull() straight to the object calling the handler. If ReturnIfNull() passes the null-check, the flow should continue in the handler..

I'm unexperienced with Delegates & Actions, can they play some role in fixing this? Or is it not possible at all?

Thanks in advance