@raulmorris since iFixit does not yet have a guide for this, Use something like the one [https://www.sosav.fr/guides/mobiles/samsung/galaxy-a70/carte-mere-camera-arriere|from here] It is written in French so use a browser that can translate it. You will need a good heat source to loosen the adhesive for the rear caver. Remember to reapply heat often to ensure that the adhesive stays soft. that is the trickiest part of this repair. Anytime you feel resistance when opening it, reheat.
While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.