Random robot name generator in format of XX123 where XX : letters from A to Z

RandomRobotNameGenerator.cs

var name = Guid.NewGuid()
    .ToString()
    .Aggregate("", (acc, x) =>
    {
        return acc.Length switch
        {
            < 2 when char.IsLetter(x) => $"{acc}{x.ToString().ToUpper()}",
            >= 2 and < 5 when char.IsDigit(x) => $"{acc}{x.ToString()}",
            _ => acc
        };
    });

RandomRobotNameGenerator_v2.cs

var name = Guid.NewGuid()
    .ToString()
    .Where(char.IsLetter)
    .Take(2)
    .Select(x => x.ToString())
    .Concat(Enumerable.Range(0, 3).Select(_ => $"{RandomNumberGenerator.GetInt32(0, 9)}"))
    .Aggregate("", (z, x) => $"{z}{x}")
    .ToUpper();