Every Android app gets its own private storage, which can’t be accessed by any other app. (unless you root the phone)
APKs get downloaded into private storage, and after installation, they’re immediately deleted, to save space.
I am having such problems. I "finished" an installation, but then it said "trouble with package" or something along those lines. Now my storage has like 3gb filled and I have no idea where the files are as it isnt shown when I do "analyze files"
Edit:
I "fixed" it by restarting the phone entirely. Not sure if it was just showing an incorrect value before or if it needed a reset to clear the data.
Now I just have the problem that android in all its glory decided that restarting my phone means I want all my folders deleted. After restarting AGAIN I finally got the program shortcuts to reappear, but not in folders...