You are thinking of an RCD or RCBO, readily available from the big DIY places or Lazada. If you post a photo of the CU we can suggest a way forwards.
BUT
These will (probably) stop you from dying, they won't stop you from getting anything from a tingle to a pretty noticeable shock from your appliances, particularly if they have a bunch of electronics or are "inverter" type.
Since you are renting and the landlord isn't going to spend $$$ you probably want to get a couple of the 1m long earth rods and some cable from the same place as your RCBO and earth your Class-1 appliances. You can even get 3 pin to 2 pin adaptors with a tag to install your earth connection.