Well, here is my update.
I had managed to temporarily 'fix' the shaking the same way I did the first time (after going through EVERY single fix possible, it was the only time it stopped for a bit) by setting my wifi as metered connection to stop any updates (and also stopped the
Defender too). It didn't fix itself right away, it took a 3 or more weeks to 'stabilize' (which is what I call it since I have no good explanation why this worked twice already for a little while) and finally the flickering was gone with the exception of the
little white lines at the bottom. But the overall horrible flicker was gone once more.
The first time around it lasted about 4 months flicker free. This time about 45 days. Both times it all went to hell when I went somewhere else with my surface and used the internet. As that other wifi was not set as metered, the effin updates downloaded
and installed themselves automatically (i managed to stop only one, but like a bunch of other ones got installed) and boom! the flicker was back. exactly like last time I inadvertently connected to another wifi and got the damn updates.
Not only did the flickering come back with a vengeance, the heating did too (which had stopped during the aforementioned period)....and worse. Now my BLUETOOTH doesn't work either! So NO PEN. Simply appears as not connected and nothing I do fixes it. I troubleshooted,
tried updating the drivers for the bluetooth, etc. Nothing. When I open the settings screen it says it's on, but when the action center screen pops from the right side of the screen that same bluetooth says 'not connected'.
I thought maybe the pen was the one that wasn't working properly, so I unpaired it and then tried to pair it again, and nothing happens. The little light on the pen doesn't appear and the surface doesn't detect anything, since it's the bluetooth that is
not working (I have two pens, one new, so it's not the pen. neither is getting paired or detected).
In other words, now it's overheating, flickering and the pen is no longer working. Just keeps getting better and better.
I trying really hard not to smash this thing against the wall in pure rage and frustration!!! Microsoft is truly the worst. :( merry christmas to me! (>.<)''