New player having a problem here. I initially opted to go with the Lite version after the HQ download consistently froze up at 92%, but after hearing just how poor quality the voices are on Lite, I decided to upgrade to HQ. The problem is, every time I select the HQ download, the game blackscreens and eventually crashes, and when I start it up again I have to re-download the Lite version. Anyone ever have something like this happen? I'm on Android, and have plenty of free space available.
Never used the Lite version, but have you tried searching in the FEH subreddit for threads that might have the same or a similar problem?
You could try to uninstall FEH completely from the Play Store and reinstall to try again. If nothing helps, i would try to contact the customer service from within the game.