Why is not a fortnite running on the huawei mate 20 lite?

I have a question unzwar running on my huawei no fortnite mobile although it should actually be sufficient in terms of performance it has 4gb RAM and an octa Core Android 9pie is also installed

Because your phone is not in the list. I do not think any of Huawei's lite models are on the list.

I do not understand that fortnite even runs on a normal s7

You can't always understand everything. Unfortunately, the world is not logical.