How can I permanently enable the news preview on Android 9?

I have a small problem, because since I have updated my phone (huawai p10) from Android 8 to Android 9, I get no messages or notification preview more displayed (eg WhatsApp or Instagram)

Neither on the lock screen, nor in the status bar when the phone is unlocked. I only see "1 notice" or "1 new message".

BUT:

If I have unlocked my phone and WhatsApp open or had, I will see the preview… As soon as I lock the phone again, I get it no longer displayed.

I have already tried all possible settings (both notification, and security settings) and even my phone back to factory settings, but all without success…

I hope someone can help me.

To the pictures:

This is displayed to me if WA was not opened

This is shown to me after I have opened WA (until I lock it again)

To my mobile:

Huawei p10

Android Version: 9

EMUI Version: 9.0.1

Did not you come up with the idea that this is the intention, so that nobody can read your news?

The problem is that I can't read it myself, but I would like that

Unlock mobile phone and read news…