Extracting Numbers from text

The most versatile way is to use VBa.

Try this UDF

Function SumCell(rng As Range)
    Dim strtmp As String
    Dim n As Long
    
    For n = 1 To Len(rng)
        If Asc(Mid(rng, n, 1)) >= 48 And Asc(Mid(rng, n, 1)) <= 57 Then
            strtmp = strtmp & Mid(rng, n, 1)
        Else
            strtmp = strtmp & " "
        End If
    Next
    strtmp = WorksheetFunction.Trim(strtmp)
    SumCell = Evaluate(Replace(strtmp, " ", "+"))
    
End Function

Use in worksheet

Formula:

=SumCell(A3)