Add double quotations " for the multiplied numbers

I need to add double quotations " for the multiplied numbers for the given strings.
The multiplication operator (as a string) is either "x" , "X" or "*".
I have used the below function to extract the multiplied numbers, originated question Here.

Option Explicit
Option Compare Text

    Function RegexExtractt(str, Optional pos As Integer = 0) As String
    
        Static re As Object
        If re Is Nothing Then Set re = CreateObject("vbscript.regexp")
        
        re.Pattern = "\d+(?:\.\d+)?(?:''|""|in(?:ch)?\b)?(?:\s*[*x]\s*\d+(?:\.\d+)?(?:''|""|in(?:ch)?\b)?)*\s*[*x]\s*\d+(?:\.\d+)?"
        re.Global = False
        re.IgnoreCase = True
        
        If re.test(str) Then
            RegexExtractt = re.Execute(str)(pos)
        Else
            RegexExtractt = vbNullString
        End If
    
    End Function 

If you are ok with doing a second replace for "" to " after obtaining for example this result string 2"*3""*5" string you could first do:

"?\s*([xX*])\s*(\d+(?:\s*\.\d+)?)"?

The pattern matches

• "?\s* Match an optional " and optional whitespace chars
• ([xX*]) Capture one of x X * in group 1
• \s* Match optional whitespace chars
• (\d+(?:\s*\.\d+)?) Capture 1+ digits with an optional decimal part in group 2
• "? Optionally match "

In the first replacement use the 2 capture groups between double quotes "$1$2"

See a regex demo.

Based on your previous questions, this is my two cents:

(\d+(?:\.\d+)?)(?:''|"|in(?:ch)?\b)?(?:\s*([*x])\s*(?=\d+(?:\.\d+)?))?

Replace with:

$1"$2

See this online demo.

Invoke this through:

=RegexReplace(A1,"(\d+(?:\.\d+)?)(?:''|""|in(?:ch)?\b)?(?:\s*([*x])\s*(?=\d+(?:\.\d+)?))?","$1""$2")

Note: This is based on the replace-function as per your linked previous question, which is case-insensitive per design.

Also, maybe your sample data is a bit too simplified. I can't imagine this to be working on actual data which may contain digits in other places you want to leave untouched.

You can use the following VBA function, which covers all cases of the example:
(with a caveat: Things are not always as they seem... there is the unprintable character with code 160, it looks like a space -code 32- but it's not.)

'The code don't work if use Option Compare Text because of x and X
Public Function doTheJob(s As String) As String
   Const qt = """", m0 = " ", m1 = "x", m2 = "X", m3 = "*"
   Dim t As String, pa As Integer, pz As Integer
   t = Replace(s, m0, " ")
   pa = InStr(1, t, " ")
   pz = InStrRev(t, " ")
   doTheJob = Left(t, pa) & Replace(Replace(Replace(Replace(Replace(Trim(Mid(t, pa + 1, pz - pa)), qt, "") _
                  , " ", ""), m1, qt & m1), m2, qt & m2), m3, qt & m3) & qt & Mid(t, pz)
End Function
 

'The code below works WITH or WITHOUT Option Compare Text
Public Function doTheJob(s As String) As String
   Const qt = """", m0 = " ", m1 = "x", m2 = "X", m3 = "*"
   Dim t As String, pa As Integer, pz As Integer
   t = Replace(s, m0, " ")
   pa = InStr(1, t, " ")
   pz = InStrRev(t, " ")
   t = Replace(Replace(Trim(Mid(t, pa + 1, pz - pa)), qt, ""), " ", "")
   If InStr(1, t, m3) Then
      t = Replace(t, m3, qt & m3)
   Else
      If InStr(1, t, m1) Then
         t = Replace(t, m1, qt & m1)
      Else
         t = Replace(t, m2, qt & m2)
      End If
   End If
   doTheJob = Left(s, pa) & t & qt & Mid(s, pz)
End Function