I’m using this fitBag (the 3rd item in this table https://source.puri.sm/Librem5/community-wiki/-/wikis/Tested%20Accessories#cases) and I was since the beginning afraid that the L5 could fall down while pulling it out of the bag or putting it in again. And yesterday it happened. I was able to put my shoe on the point where it would hit the ground and so no damage happened. As a rule of thump I will do it in the future only above a table or above my lap.
A good case should protect the display and the four corners of the L5 and should allow that the heat goes out too.