Precision 7550 power problem

Hello, I bought a Precision 7550 on 10/09/2020. It arrived in Milan, Italy on Monday the 28/09/2020. From Day 0 I had problems with charging this laptop. In this post, I will describe the problem, ignoring all the bad issues I had with DELL service like technician sent but never arrived, or like technician arrived at 13:15PM while I was eating, or like technician without Linux competence sent to solve a problem on a Linux machine, not to mention the times I've waited a quarter of an hour on the phone only to hear the phone hang up in my face (all this in one month, could you belive it?).

Well, before we start talking about this, I would remember you that I am a private customer that bought this laptop by exchanging ~3080€ VAT included, and that the laptop was sold with Ubuntu 18.04.

The BIOS version is 1.4.0, I have personally updated through LVFS on the 28/09/2020. The problem is that sometimes the 180W power adapter is recognized, and sometimes it is not. While the OS is running, I can tell you that the adapter is not recognized because the processor is slow, so by running cat /proc/cpuinfo|grep MHz you will always get low speed.

If I restart the machine and enter the BIOS, this fact is confirmed because it says Unknown in the screen page related to the power. If you remove the power connector, and then insert it again, if you're lucky, it will be recognized and will shows 180W. If you're not lucky, well, try again, at some point it'll work.

So, let's get to the attempts that was made to solve this. In the very first call to the support, the technician guided me to reset the settings to the factory. This seems to work, but after the call was terminated the problem shows up again.

In the second call, the technician realized that it could be a problem with the power adapter, and ordered a replacement. Unfortunately, after the replacement arrived, the problem was still there.

This leads us to the third call, where the technician realized that it could be everything but the power adapter, so it ordered to change the motherboard and other pieces related to power, I guess.

Well, this actually hasn't worked. I told them that maybe it is the 1.4.0 version of the BIOS that introduced this flaw, but they seem to ignore this fact.

Now I'm waiting for a third replacement of everything, motherboard, power adapter and who knows what. And then, guess what they will try to do? They will replace the entire laptop, this will lead us to the fourth replacement.

Have you experienced something like this with DELL, or worst? Have you had this problem with Precision 7550? What if it really was the BIOS update through LVFS? I repeatedly asked them if they actually have tried to reproduce the error, but they never replied me. How is it possible that one don't try to reproduce this? They could have used my first motherboard.

Besides all this questions, that is one I really ask this community to reply. Is it worth to wait until this will eventually be fixed, or do you advice me to get a better laptop from a better vendor?

Thank you.