I have the same problem and I have tried literally anything but it keeps happening.
I have a Macbook Pro 13-inch, 2017 with Big Sur.
These are the symptoms of the problem:I open my laptop in the morning, the internet connection seems working for a moment and it suddenly stops.
I click on wireless icon, I click Network preferences, and I am unable to see configurations as the windows seems to be stuck.
By checking Activity Monitor I see the kernel_task process with high CPU.
I am unable to restart or shut down the laptop unless I press the power button.
After restarting I either have no problems or, often, I am even unable to switch on the wi-fi at all. It just doesn't seem to work and I am forced to restart again.
If, after restarting the problems are solved, everything works fine... until the next morning! I usually put the laptop on sleep and the following morning I experience these issues.
Now, this is what I have tried to do:Completely re-installed the whole operative system and been careful not to install VPNs or software that could trigger these issues... At first it seemed to work fine, but I started experiencing these problems again after some days.
Tried resetting NVRAM and PRAM (don't remember which one exactly) but just been pressing those keys when the laptop starts, with no luck
Uninstalled VPNs software (thinking they were the problem)
Created a new Network Location (as suggested in some websites). It just doesn't solve anything.
Tried booting on safe mode and restarting, but this cannot be the solution anyway!
Some details about what may causing it:I am using a bluetooth mouse, can it be a problem with the bluetooth? (I cannot find a link though)
I have a usb hub, with hdmi external monitor and usb keyboard connected to it (wondering if these can affect the wifi hw? (not sure)
I usually put my macbook on sleep (and the problems always appears in the following morning, this may be a trigger for the issue to happen)
I am seriously trying to find a solution because I have wasted hours and hours of time without being able to connect to internet and lost track of what work I was doing. This is really annoying.
I am going to try to talk with Apple Support this week and hoping that someone may help. I would not mind to have my laptop replaced as I am not 100% sure this is just a software issue.. but for some reasons it started after installing Big Sur. I have used my laptop with no issues before, for over 3 years, so...
I hope someone from Apple is monitoring this thread and can help us!
It's hard to speak with someone because of the pandemic, but I would appreciate if someone from Apple could get in touch for this problem.
I will update you if I have any news guys.