we are all stupid, but the computer is even stupider. Thats why game dev is so hard :).
I was about to add some additional info, just fyi stuff:
quick way to check the static mesh properties - just click the floor static mesh in the viewport, press ctrl+e, and then in details panel type “collision”
if you needed to change the Collision Presets, you can select “custom” from the dropdown and edit the Trace Responses as needed.
Also note that it is possible to create custom trace channels in the project settings. This way you could put some objects on a channel just for them, so a linetrace could ignore everything except for one specific type of thing. That can come in handy sometimes. Just a possibility to keep in back of your mind.