CombinedFilter.cs

var combinedFilter = new CombinedFilter()
{
    Operator = CombinedFilter.LogicalOperators.Or,
    ChildFilters = new[]
    {
        new FilterClause()
        {
            FieldName = nameof(NewsDto.Title),
            Operator = FilterClause.StringOperators.Contains,
            FieldValue = uniqueFilter,
        },

        new FilterClause()
        {
            FieldName = nameof(NewsDto.Title),
            Operator = FilterClause.StringOperators.Contains,
            FieldValue = secondItemUniqueFilter,
        },
    },
};