There absolutely still has to be a structure! And way too many do look pretty much exactly like a handful of spaghetti flung onto a page and called a script. While almost any trope CAN be done well, so many of the ones that I commonly see attempted fall super, super flat.
Oh jeez, I can't think of an example at the moment, but I've seen two or three shitty horror movies recently that were set up as having a frame story that had no concluding part! I hate it!
Same goes for things that are explicitly marketed and framed as found footage and then just randomly have ordinary multi-camera shots of a conversation or something.

I could see that being an appealing thing to write! Those kinds of... "too big/too much/too evil" horror can be really effective. Eldrich horror usually goes for that, but I think there are options to explore it beyond that.