Option Explicit
Sub t()
Dim rng As Range, ar As Range
Dim x, arr, arrOut(), i&
Dim dFrom#, dTo#

Set rng = Intersect(Range("J:J"), ActiveSheet.UsedRange).SpecialCells(xlCellTypeConstants, xlNumbers)
If rng Is Nothing Then Exit Sub

dFrom = [o1].Value2
dTo = [p1].Value2
ReDim arrOut(rng.Count - 1): i = -1

    For Each ar In rng.Areas
        arr = ar.Value2
        If Not IsArray(arr) Then arr = Array(arr)
        
        For Each x In arr
            x = CDbl(x)
            If x > dFrom And x < dTo Then i = i + 1: arrOut(i) = Format(x, "DD/MM/YYYY hh:mm:ss")
        Next x
    Next ar

If i = -1 Then Exit Sub
If i <> UBound(arrOut) Then ReDim Preserve arrOut(i)
MsgBox Join(arrOut, vbLf)
End Sub