My management office charge RM50 for access card if misplaced. Key maybe can duplicate outside

That auntie is seasoned renter...she knows you are trying to charge more...

Well you have the right to set a deposit but you need to justify what is it for

You already mentioned it’s for key + access card. If you set an amount that is so high, renter will ask. You can show evidence from management office on how much it usually cost to replace

If you are first time land lord, best to consult other land lords how they manage all this