deadpoolio

Search 'Dell 7567 Notebookcheck' or 'Dell 7577 Notebookcheck'. They have tested the IPS panel models (7567 has model with poor TN panel). It's totally fine for everyday use, as long as it's not TN panel.

Try rechecking every led connection to your motherboard and your pc case. Further check this video out to get your doubts cleared
 

For cybersecurity and networking, you probably need linux in vm's to test things, 2 to 3 at the same time is not uncommon. So I would get a hex core, 32GB RAM (Can upgrade later or DIY), and a 15 inch

It's about as big as you would want a laptop to be for all day carrying around. The battery is very good for a gaming laptop and the build is decently solid. The cooling is excellent. 
 
One minor drawback is that the screen flexes. Not the hinge, the actual screen. It doesn't impact usage at all but it does look kinda cheap.
 
 

The IPS panel has pretty good colours, but doesn't get too bright. It's usable in the light but it's not going to be incredibly clear. It doesn't glare much. 
 
While the laptop is excellent, new laptops with 6 core CPUs are out, and I would recommend one of those. 

If you're gonna be doing cybersecurity I'd make sure whatever device you go with that it plays nice with Linux. I know the XPS series of laptops are some favorites among security experts, so maybe check out an XPS 13 or something.

Which i7? For ULVs:
 
That's what you would expect in most laptops.
 
I would suggest a Thinkpad P, however they are probably out of your budget if you buy them in India. If you're going to buy in US then get P51/P50 or even P71/P70. Nevertheless you might want to wait for refresh: P52 and P72 are coming.

Nope, performance not much better than 8250U/8350U due to cooling and TDP limitations.
You're complaining a non gaming laptop with no gaming features like 120Hz 5ms panel and anti ghosting keyboard?
Always look for reviews first. Design means nothing to me.