The guest middleware RedirectIfAuthenticated is not working for me correctly with InertiaJs

Hello,

I am currently in the process of migrating to InertiaJs for our Laravel applications. I could not use Breeze. But I fired up a new Laravel Project and copy pasted the required Files over. Everything is working except the guest middleware. So currently authenticated Users can still visit the login and registration page. I am unsure how I can fix this. Any hints would be appreciated.

The Login:

    public function store(LoginRequest $request)
    {
        $validated = $request->validated();
        $securityKey = $validated['securityKey'];

        if ($securityKey !== config('auth.BACKEND_SECURITY_KEY')) {
            return redirect()->back()->withErrors(['error' => 'Invalid Login']);
        }

        $request->authenticate();

        $request->session()->regenerate();

        return redirect()->intended(config('wd.authentication.redirects.after_login'));
    }

The middleware:

    public function handle(Request $request, Closure $next, ...$guards)
    {
        $guards = empty($guards) ? [null] : $guards;

        foreach ($guards as $guard) {
            if (Auth::guard($guard)->check()) {
                return redirect(RouteServiceProvider::HOME);
            }
        }

        return $next($request);
    }

I noticed that the StartSession middleware runs currently after the RedirectIfAuthenticated. I think that might be the issue because this Auth::guard($guard)->check() currently returns null.