Making variable strings of text italics in Excel VBA

I have a range of cells with varying lengths of text.

These can look like:
"(first)"
"Here's another (longer string of text) for the example"
"And yet another much (much much longer string of text for reasons) that goes on and on"

I want to italicize text between ().

All solutions I found online look for .Character lengths, as in how many characters to start/stop.
Is there a way to italicize everything between () instead?

I tried this code from an SO question but changed the parts I thought would matter:

Sub ITALICS()
Dim X As Long, BoldOn As Boolean
BoldOn = False 'Default from start of cell is not to italic'
For X = 1 To Len(ActiveCell.Text)
    If UCase(Mid(ActiveCell.Text, X, 1)) = "(" Then
        ItalicOn = True
        ActiveCell.Characters(X, 1).Delete
    End If
    If UCase(Mid(ActiveCell.Text, X, 1)) = ")" Then
        BoldOn = False
        ActiveCell.Characters(X, 1).Delete
    End If
    ActiveCell.Characters(X, 1).Font.Bold = BoldOn
Next
End Sub

All it did was remove the () from my cells.

Solution

Your current code only checks for the parentheses and deletes them, and also uses Bold instead of Italic, and without properly tracking the range between ( and ).

Is this what you are tying? I have commented the code. Let me know if you still have questions.

Option Explicit

Sub Sample()
    Dim ws As Worksheet
    Dim rng As Range
    
    '~~> Change this to the relevant sheet
    Set ws = Sheet1
    
    '~~> Change this to the actual range
    Set rng = ws.Range("A1:A2")
    
    Dim aCell As Range
    Dim txt As String
    Dim startPos As Long, endPos As Long

    '~~> Loop through each cell in the selected range
    For Each aCell In rng
        '~~> Ignore cell which has formula
        If aCell.HasFormula = False Then
            txt = aCell.Value
            startPos = InStr(txt, "(")
            endPos = InStr(txt, ")")

            '~~> Ensure both ( and ) exist and are in the correct order
            If startPos > 0 And endPos > startPos Then
                '~~> Apply italics only to the text between ( and )
                '~~> Also we add +1 to startPos to skip the opening bracket
                '~~> Finally Subtract 2 to exclude both parentheses from formatting
                aCell.Characters(Start:=startPos + 1, Length:=endPos - startPos - 1).Font.Italic = True
            End If
        End If
    Next aCell
End Sub

BEFORE:

AFTER: