Autofill formulas down rows of new data

Hello! I am new to VBA. I am having trouble autofilling my formulas down. I add in new data to this spreadsheet each month. I am wanting to copy formulas from column P-AX (all different) down to the last line of data. Right now I have 417 rows, in the future however I will have much more. Please help!

Sub Copyformulas()
'
' Copyformulas Macro
' copy formulas
'

    Selection.AutoFill Destination:=Range("J2:J417")
    Range("J2:417").Select
    Selection.AutoFill Destination:=Range("K2:K417")
    Range("K2:417").Select
    
End Sub

But then it will only autofill to row 417, it will likely increase by 100+ next month, and so on..