Flutter: Null check operator used on a null value, late keyword not working either

I am trying to render a simple 10×10 grid of characters on my application, but the grid boxes are not being rendered properly (only the characters are being displayed, not the boxes themselves), and I’m getting an exception stating: Null check operator used on a null value. I have tried using the late keyword, but that gives me the exception "LateInitializationError: Field ‘grid’ has not been initialized." Any ideas on how to get around this would really help. Thanks!

class _MyHomePageState extends State<MyHomePage> {
  Grid? grid;
  List<String> selectedList = [];
  var isLoaded = true;
  @override
  void initState() {
    // TODO: implement initState
    getData();
    super.initState();

  }

  getData() async{
    grid = await RemoteService().getGrid();
    if(grid!=null){
      print('Payload received');
      setState(() {
        isLoaded = true;
      });
    }
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Wordsearch'),
      ),
      body: Visibility(
        visible: isLoaded,
        replacement: const Center(child: CircularProgressIndicator()),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            for(var i=0;i<10;i++) Row(
              children: [
                for(var j=0;j<10;j++) GridItem(
                    item: grid!.grid[i][j],
                    isSelected: (bool value){
                      setState(() {
                        if(value){
                          selectedList.add(grid!.grid[i][j]);
                        } else{
                          selectedList.remove(grid!.grid[i][j]);
                        }
                      });
                    })
              ],
            )
          ],
        )
      ),
    );
  }
}