I may have found a soft solution, or at least the cause of the bug. I notice that the frame I was editing in, “Search/view historical analyses”, had a “/” in it. I removed the forward slash, and when I went to export an asset in the frame it allowed me to name the file and didn’t create a subfolder. If I try to export assets in frames that have "/"s in the name, Figma will create a subfolder and remove naming options.
Seems like unintended behavior to me.
However, removing my slashed destroys my folder structure in Assets panel, and since there is no other way to create folders of different kinds of assets without using a “/” in the name, it’s not a workable solution for me.
It seems to me Figma really doesn’t care much for developers using their software. We still have no native SCSS, SASS or LESS support, no custom units such as em or rems, no support for CSS variables and this. The fact that this tickets dates from 2021 is just sad 
This is VERY annoying. Layer names shouldn’t affect export folder structure.
10000% for that! I hope it would an option in near future!
Plus one on this feature! Simple stuff. Come on, guys! 
Yes, PLEASE, add the option. I love Figma, but having all these folders when I just want to export a few screens is excruciating
Hey there. I use slashes / everywhere, to define hierarchy and stuff. Some have said that it creates a mess while exporting.
I can confirm. One of the developers I work with sent me this picture:
Is this enough to understand the problem? A simple checkbox on the export panel would help a lot. I’m sending the link of this post as a reply to that developer question: “Is there a better way to export things in Figma?”.
yes! still want this 2 years later! 
Just found this plugin that let’s you export all selected frames into 1 single zipped file.