Internal memory full (Huawei P8 lite 2017)?

I have a problem and I really hope that someone can help me here. I have the Huawei P8 lite 2017 with 16 GB and my memory is full. I only installed 3 apps (all of them use very little memory) and the pictures and videos are all on an extra memory card (which means they don't use any memory). I can no longer make updates and at times can no longer access WhatsApp. I've already tried everything, restart, reset to factory settings, clear the cache of my apps, delete all folders for files, clean up the memory, but none of it helped. When I go to the display that shows me what is being used up so much memory: "Other: 10 GB, firmware: 5.75 GB", the rest is 0 GB everywhere. What exactly is other and firmware and how can I delete it!

I hope so much that one of you can help me.

LG

Tap on it on others, then you will see what is saved under Others.

Unfortunately, you can't tap on it, but thanks anyway for your answer.

Then download the app, then call up the main memory and everything in the internal memory will be displayed

https://play.google.com/...ilemanager

If I go to the Files app on my P30 Lite then I have internal memory, if I tap on it, everything that is stored on it is displayed to me individually

So I just did that and in the main memory there were two files that used up about 10 MB. I deleted it but if I'm honest it didn't work. But thanks anyway so I now know that it can't be due to such files