Huawei cell phone no longer opens many apps?

My Huawei mate 10 lite is only about 2 years old. Since today it happens very often that when I open apps, regardless of whether it loads games, Google, etc., the app closes again immediately. I restarted my mobile phone and also uninstalled and reinstalled the apps, but that only helped for a short time.

Can I fix this or do I have to buy a new one?

You need to update WebView. You can easily do this in the PlayStore.