csharp
public class PropertyIndexPopulator : IndexPopulator
{
    private readonly IContentService _contentService;
    private readonly PropertyIndexValueSetBuilder _propertyIndexValueSetBuilder;

    public PropertyIndexPopulator(IContentService contentService, PropertyIndexValueSetBuilder propertyIndexValueSetBuilder)
    {
        _contentService = contentService;
        _propertyIndexValueSetBuilder = propertyIndexValueSetBuilder;
        RegisterIndex("PropertyIndex");
    }

    protected override void PopulateIndexes(IReadOnlyList<IIndex> indexes)
    {
        foreach (IIndex index in indexes)
        {
            IContent[] roots = _contentService.GetRootContent().ToArray();
            index.IndexItems(_propertyIndexValueSetBuilder.GetValueSets(roots));

            foreach (IContent root in roots)
            {
                const int pageSize = 100;
                var pageIndex = 0;
                IContent[] descendants;
                do
                {
                    descendants = _contentService.GetPagedDescendants(root.Id, pageIndex, pageSize, out _).ToArray();
                    IEnumerable<ValueSet> valueSets = _propertyIndexValueSetBuilder.GetValueSets(descendants);
                    index.IndexItems(valueSets);

                    pageIndex++;
                }
                while (descendants.Length == pageSize);
            }
        }
    }
}

csharp
public IEnumerable<ValueSet> GetValueSets(params IContent[] content)
    {
        foreach (var propertyPage in content.Where(CanAddToIndex))
        {
            using var _ = _umbracoContextFactory.EnsureUmbracoContext();
            var property = _?.UmbracoContext?.Content?.GetById((int)propertyPage.Id)?.Cast<PropertyPage>();

            if (property != null)
            {
                var indexValues = PopulateValues(property);
                yield return new ValueSet(property.Id.ToString(), IndexTypes.Content, property.ContentType.Alias, indexValues);

            }
        }
    }

    private bool CanAddToIndex(IContent content) => content.ContentType.Alias == "propertyPage";

    private Dictionary<string, object> PopulateValues(PropertyPage property)
    {
        using var _ = _umbracoContextFactory.EnsureUmbracoContext();

        var values = new Dictionary<string, object>()
        {
            // Populate standard fields
            [UmbracoExamineFieldNames.NodeNameFieldName] = property.Name!,
            ["name"] = property.Name!,
            ["id"] = property.Id,
            [Const.PropertyChannel] = string.Join(",", property.GetChannels().Select(x => ((int)x))),

//code skipped here (continues adding values in this way)

return values;
}