Can't see generated/imported terrain in the editor

Hi. I’m facing a serious issue. For some reason, I’m unable to see the terrain I generate (or import) in the editor. I can only see it when I’m lauching the game. My project is pretty old (2 years) so maybe it’s corrupted? I’m on 4.20.1, I’ve created another project to see if it was because of my installation but it worked fine. So I guess my game project is corrupted, or maybe I just messed around some obscure setting by accident? :confused: