Program.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

BenchmarkRunner.Run<BenchmarkArraySplit>();

[MemoryDiagnoser]
public class BenchmarkArraySplit
{
    [Benchmark]
    public string Vabka()
    {
        var array = new[] { "Привет", "меня", "зовут", "*", "Мой", "возраст", "таков" };
        var parts = array.Split("*").Select(x => string.Join(' ', x));
        return string.Join('\n', parts);
    }

    [Benchmark]
    public string Edward()
    {
        var words = new[] { "Привет", "меня", "зовут", "*", "Мой", "возраст", "таков" };
        var variables = new Dictionary<string, string>()
        {
            { "name", string.Empty },
            { "age", string.Empty }
        };

        var items = words.Select((word, index) => new
        {
            Item = word,
            Index = index,
            Group = words.Skip(index)
                .Select((wordFind, indexFind) => new
                {
                    Item = wordFind,
                    Index = indexFind + index
                })
                .FirstOrDefault(wordFilter => wordFilter.Item.Equals("*"))
        }).GroupBy(wordGroup => wordGroup.Group?.Index);

        foreach (var item in items)
        {
            var groupped = string.Join(" ",
                item.Select(word => word.Item)
                    .Where(word => !word.Equals("*")));

            var key = variables
                .Where(keyVariable => keyVariable.Value.Equals(string.Empty))
                .Select(keyVariable => keyVariable.Key).FirstOrDefault();

            if (key != null && variables.ContainsKey(key))
            {
                variables[key] = groupped;
            }
        }

        return string.Join("\n", variables.Select(wordsObject =>
            $"key: {wordsObject.Key}, value: {wordsObject.Value}"));
    }
}

public static class ArrayExtensions
{
    public static List<List<T>> Split<T>(this IEnumerable<T> array, T separator, IEqualityComparer<T>? equalityComparer = null)
    {
        equalityComparer ??= EqualityComparer<T>.Default;
        var parts = new List<List<T>>();
        var currentPart = new List<T>();
        foreach (var element in array)
        {
            var isSeparator = equalityComparer.Equals(element, separator);
            if (isSeparator)
            {
                parts.Add(currentPart);
                currentPart = new List<T>();
            }
            else
            {
                currentPart.Add(element);
            }
        }

        parts.Add(currentPart);
        return parts;
    }
}