given an array of strings, and I want to sort it, the code as follows

string[] s = ["=:rr", "2:yy", "=:hh"];
Array.Sort(s);
foreach (var item in s)
{
    Console.WriteLine(item);
}

my expected result:
2:yy
=:hh
=:rr

the actually result:
=:hh
=:rr
2:yy

From what I understand, strings are sorted based on the Unicode value of each character. ‘2’ has a Unicode value of 50, and ‘=’ has a Unicode value of 61. So why isn’t the result as expected?