Dell XPS 13 9360 i7-7560U CPU overheats, should I send the laptop in?

Dell XPS 13 9360 i7-7560U CPU overheats, fan only kicks in at high temperatures, so CPU most of the time is at or above 80°C (176 °F).

I searched on dell forums and found threads wherein other customers complained about same issue, and it seems that after replacement of motherboard + heatsink the high temp issue gets fixed.

Re-pasting CPU also wouldn't hurt, but since I bought the laptop recently, I'd rather Dell do it, since I don't want to lose warranty by cracking the laptop open.

Here's the video, no prior CPU overload, this is after laptop was turned on while it was off for quite a while, though when I entered diagnostics I waited till the default tests were automatically done and finished. It seems that CPU fan only kicks in at high (80°C temperature) and even then it only lowers the CPU temp down to like 70° and goes back to 0 RPM, is it normal? It shouldn't be, since it keeps CPU at overly high temperature! This was done while on battery (ac not plugged in).

Here's screenshot while I'm logged into OS. As you can see, CPU temperature gets abnormally high with a mild CPU load. You can test your laptop same way, just open this youtube video and see for yourself.

In my case, temperature quickly rose to high value.

I also tried to stress CPU by using HeavyLoad, I got CPU load at 100% but CPU cores almost instantly got to 90°C and started rising higher, so I stopped the test right away.

The question is, should I send the laptop in? Can dell fix it? Or should I simply return it?

I also had two other issues with this laptop:

The 45W ac adapter that came with laptop wouldn't be recognized in BIOS, so it'd give error: "AC power adapter wattage and type cannot be determined", and wouldn't charge battery while plugged in.

Sometimes it does charge battery, but only when laptop is shutdown.

2nd issue is the auto-brightness, that I managed to finally subdue after trying all these:

disabling DBC, installing latest graphics driver from Dell website, or Intel website using this method, installing latest bios, and other recommended drivers, disabling sensor monitoring service in "services.msc".

If these 2 issues could be relevant in any way to the CPU overheating.