Hi @lisasalber
Here's the [document|27608|service manual] for the model series.
Go to p.40 ''Self-Diagnostics during the normal operation'' and check if any error codes are being displayed.
Given that you've recently checked the drain hose and cleared it (was was blocking it?) I'm wondering if the ice build up under the freezer drawers might be due to a faulty door seal (aka gasket).
If the seal was torn or even worn down then not only would cold air escape from the freezer but warm, moist air could enter, whereupon it would condense to a liquid and then freeze due to the below freezing temperature. inside the compartment. Worth a check anyway.
Place a sheet of paper between the door and the door jamb and with the door closed normally i.e. no pressure on it by you to keep it closed, try pulling the paper out. It will come out with a bit of an effort but not that easily and it should definitely not fall out by itself. Do this at various points around the door, top, bottom and both sides.
If the seal is faulty then the part number is ''DA63-06538B.'' Search online using the ''part number only,'' to find suppliers that suit you best.
Here's a [https://www.youtube.com/watch?v=Z-NRd7hseDk|video] that in general shows how to replace seals in Samsung refrigerators that may help.