Hi Lewis, sorry, missed your previous comment. Thanks for the info re index class, actually a week ago I came to that by myself also. Now I'm trying to get the index properly populated. I intentionally added extra logging and see that content nodes are indeed get indexed. But by some reason in backend Umbraco still does not show expected status.

My classes are quite close to Umbraco docs. Here is Populator method:

    protected override void PopulateIndexes(IReadOnlyList<IIndex> indexes)
{
    foreach (IIndex index in indexes)
    {
        //Go over all the content and index it if it fits the criteria
        IContent[] roots = _contentService.GetRootContent().ToArray();
        index.IndexItems(_newsIndexValueSetBuilder.GetValueSets(roots));

        foreach (var root in roots)
        {
            const int pageSize = 10000;
            var pageIndex = 0;
            IContent[] descendants;
            //Weird syntax, but it follows the Umbraco docs
            do
            {
                descendants = _contentService.GetPagedDescendants(root.Id, pageIndex, pageSize, out _).ToArray();
                IEnumerable<ValueSet> valueSets = _newsIndexValueSetBuilder.GetValueSets(descendants);
                index.IndexItems(valueSets);
            }
            while (descendants.Length == pageSize);
        }
    }
}

and here is GetValueSets method with extra logging. Here I am adding all the content node's properties as index field:

    public IEnumerable<ValueSet> GetValueSets(params IContent[] contents)
{
    foreach (var content in contents.Where(x => _contentTypes.Contains(x.ContentType.Alias) && x.Published))
    {
        _logger.LogDebug("---------------- Indexing content item ID: {id}, name: {name}", content.Id, content.Name);

        var indexValues = new Dictionary<string, object>
        {
            //This is where we assign our fields defined in options
            [UmbracoExamineFieldNames.NodeNameFieldName] = content.Name!,
            ["id"] = content.Id,
            ["parentId"] = content.ParentId,
            ["nodeName"] = content.Name!,
            [SearchKeys.POSTED_DATE_FIELD] = content.CreateDate,
            [SearchKeys.POSTED_DATE_TICKS_FIELD] = content.CreateDate.Ticks
        };

        foreach (var property in content.Properties) indexValues[property.Alias] = property.GetValue();

        var valueSet = new ValueSet(content.Id.ToString(), IndexTypes.Content, content.ContentType.Alias, indexValues);

        yield return valueSet;
    }
}

Log messages from this method come through and I see them in Umbraco logs, but index is still empty and configured for 8 fields instead of many more. In Azure Search service - the same....... So still fighting..