Where should I save my custom generated artifacts on the iOS device in order to pull them out?

I develop a game with Unreal Engine and covering it with the automation tests. During the tests I take screenshots at the specified folder. Now I decided to run my tests with AWS Device Farm and I can not figure out where to save my screenshots to pull them out with. How do I get the absolute path to "Documents/Library/Media or tmp folders" inside my app?

The path to the Documents folder (according to the Appium log file) was : /tmp/scratchA5jsh1.scratch/app-sandbox-mount-tXrZsG/Documents/

I tried to find all the paths that match this pattern using the iOS device's environmental variables and UE FPaths. I have not found anything even remotely similar.. Please help.