Flutter Sliver A-Z side menu list

Question

I tried alphabet_scroll_view and azlistview, but it doesnt work with customscrollview and sliverlists.

I have:

customscrollview
  Appbar - pinned
  title
  sliverlist (10 items)
  title
  sliverlist (10 items)
  tabs (contacts, favorites) - pinned
  contactswidget
    sliverlist (+ a-z list view)

I need exact functionality that azlistview has, but in sliver version.

tried everything i could think of, but sliverstack just doesnt fix the side menu, scrolljump is wrong, scrollable.ensurevisible jumps to the bottom and sort of these problems.

EDIT: my structure is:

Customscrollview

• appbar
• search
• widget
• widget
• tabs
• widget
• sliverlist (with missing AZ menu)

class TestModel {
  String tagIndex;
  String name;
  TestModel({required this.tagIndex, required this.name});
}

class IndexPartial extends ConsumerWidget {
  final bool definitionsOnly;
  const IndexPartial({super.key, this.favorites = false});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final state = ref.watch(indexProvider(favorites));

    final List<TestModel> contacts = [
      TestModel(name: 'eeee', tagIndex: 'E'),
      TestModel(name: 'eeeeee', tagIndex: 'E'),
      TestModel(name: 'pp', tagIndex: 'P'),
      TestModel(name: 'ppp', tagIndex: 'P'),
      TestModel(name: 'pppp', tagIndex: 'P'),
      TestModel(name: 'ppppp', tagIndex: 'P'),
      TestModel(name: 'w', tagIndex: 'W'),
    ];

    return state.when(
      data: (data) {
        return MultiSliver(
          children: [
            //AZ list index
            SliverPadding(
              padding: const EdgeInsets.only(right: 45),
              sliver: SliverList(
                delegate: SliverChildBuilderDelegate(
                  (BuildContext context, int index) {
                    return Container(
                      height: 200,
                      color: Colors.yellow,
                      child: Text(contacts[index].name),
                    );
                  },
                  childCount: contacts.length,
                ),
              ),
            ),
          ],
        );
      },
      error: (error, stackTrace) {
        ...
      },
      loading: () {
        ...
      },
    );
  }

EDIT: i tried alphabet_list_view Since its listview i get: LateInitializationError: Field 'geometry' has not been initialized. i have customscrollview and another customscrollview from alphabet_list_view nested is not the way, shrinkwrap is out of question.