Storage issues with Android tablet

[Velaryon]

I'm having a problem that I feel like can't be just a me thing, so I'm hoping somebody has a solution.

I've got a Samsung tablet that I literally only use to play one game (Fate Grand Order, if it matters, though I used to play Summoners War on it and would have this same problem). I don't use the tablet for anything else - I don't have any other apps downloaded, I don't have any pictures, videos, or music stored on it, I don't check my email on it, and I've uninstalled as much of the default software as I can get away with. I might occasionally use the browser when my phone is unavailable (like once a month at most) but not for very much.

And yet my tablet is always telling me it's almost out of space. I go into the storage menu under settings and it claims to have 447 MB of available space in the device memory, yet tells me I don't have enough storage space when I'm trying to download small updates to the game. It also tells me that I have 2.39 GB of space used by "miscellaneous files," yet when I click on the Miscellaneous Files thing it says there are no items in there. FGO has been moved to my SD card, which has tons of space available, yet none of this allegedly available space seems to matter.

What I've done in the past is just go through every app on the device and clear caches, delete data, etc. to try and scrounge up a few extra KB to fit in updates, and that usually works for a while. But eventually I reach a point where the only thing I can do is factory reset the device, which is a huge hassle to deal with. Then I'm able to redownload the game with all the updates and it doesn't even tell me that I'm low on space... for a while. Eventually after some updates it will start telling me I'm getting low on space again and the cycle repeats. Unfortunately, it seems to happen a little bit faster each time, as the last reset was only in late August.

So fellow Playgrounders, my question is: what is taking up all the space, and what can I do about it that doesn't involve yet another total factory reset of the device?

[thatSeniorGuy]

Give DiskUsage a go, which will give you an exact breakdown of what your phone's storage is being used on (the app hasn't been updated in a while, but still works fine on my modern-ish phone). This Reddit thread also has a few more suggestions.

[Yora]

Ha, story of my life.

In the file browser, click on "more" in the upper right corner and select "show hidden files". Then you can start looking for those mystery miscelaneous files. Cleared a good gigabyte of junk from my 8gb tablet recently.

[Melayl]

I've found Avast (free antivirus/disc cleanup) to be helpful in finding and getting rid of all of that hidden storage stuff, too.

[jhonalbert]

If you download so many videos from youtube then it will effect your storage.

[Tarmor]

I've found Avast (free antivirus/disc cleanup) to be helpful in finding and getting rid of all of that hidden storage stuff, too.

Avast is fine in it's free AntiVirus capacity, but its drive cleaner has to be purchased. (Much better and more reliable free products exist)
Yora's suggestion sounds a lot more relevant, and a free disk check program might help (like thatSeniorguy suggests) but make sure its reputable.

[Bohandas]

I would not be surprised if this turned out to be some scam by the manufacturer to get people to upgrade their tablets. The only part that doesn't fit is that that sort of thing is more Apple's M.O. than Samsung's