Dynamic brightness control, Backlit keyboard, and Audio issues

Hello,

I've recently received an Inspiron 14 5490 and I'm having trouble with a few of the design features:

1. The screen brightness keeps adapting via the 'Dynamic Brightness Control' feature, and there is no option to disable this under either 'Display' or 'Battery' in the system settings. 

2. The backlit keyboard keeps timing out after a few seconds of inactivity. It then turns itself back on (once every few minutes) despite nothing being touched (no keys pressed, mouse not moved etc). Incredibly infuriating when watching videos etc

3. With headphones plugged in, a minor 'static' sound can be heard. Often the audio drowns this sound out, but it can be heard at quiet points or when no audio is playing. The headphones worked perfectly on my previous laptop.

4. Every once in a while, audio in videos when played through the built-in speakers seems to 'bleep' as if the audio crashes for a split second.

Considering returning the laptop if these issues can't be resolved, as although they are minor individually, dealing with all of them on a brand new £800 laptop is very annoying and it does not give me confidence that the laptop is built to last a few years.

Can anybody help?

Many thanks