Grey screen (extremely long loading) after update

Hello,
I think Life has decided that’s it’s time to learn about Desktop Manager and GUI.
I have a “working progress” pc, which has a Intel i5-10400F and a temporary Nvidia 8600GT.
Everything worked pretty fine, but after last (24th October) upgrade, I get a grey flickering screen (tv shows that resolution change continuosly from FULLHD to 1024x768 and the opposite) after boot; mouse pointer is present and movable.
I tried a fresh install and it worked, but after the first huge upgrade, the very same problem represented.
Note: I picked “free” in driver option, because with “non-free” installation stucked in the begin.

I searched online and applied a plenty of solutions, but I’m completely ignorant about Desktop-Manager and Gnome in particular. So, can someone helps me and also teach me what the commands mean, about config file, etc etc, to solve this problem?
Because I mostly followed some solution, but without any clear idea of what they did.

Ps: I miss the “newbie” section, I hope not to have misposted.

UPDATE:
$journalctl /usr/bin/gnome-shell
JS ERROR: Could not load extention arc-menu@ligem33.com: Error Missing metadata.json [...]

I thought to remove the package gnome-shell-extension-arcmenu but I cannot because of dependencies with manjaro-gnome-assets
I tried to install xdg-utils but it solved nothing

Enable/disable arcmenu. It’s name has changed from arc-menu -> arcmenu

1 Like

sudo gnome-extensions disable arc-menu@linxgem33.com
is the only command that gives output, every other arc-name did nothing: sometimes the command gave no output, more often it stuck in nothing and I had to CTRL+c to take control back.
Also gnome-extensions list or ... show arc-menu@linxgem33.com didn’t output nothing.

Anyway, the output of the only-working command is:
dconf warning failed to commit changes to dconf: cannot autolaunch D-bus without X11 $DISPLAY

EDIT 0:
After that I tried to delete the folder inside /usr/share/gnome-shell/extensions/...
and then journalctl: the error disappeared, but the problem is still present. Grey screen with operative mouse.

EDIT 1:
I left the pc in that state for a while and the desktop loaded! Not the screen image, but still, it seems quite usable.

Hypothesis
since the gpu is quite old and with only 256 mb, could it be the lack of VRAM?
Before the problem I had to disable Chrome hw-acceleration because the pc freezed for a couple of minute (I suppose for RAM-VRAM memory loading).

Wrong(edit)

In the last update I notice a info about QGnomePlatform engine: is it possible that uses more video-memory and that’s why I get problem?

I keep putting info that maybe are useful (please, don’t let me alone or I’ll cry)
While grey screen is showed, htop report /usr/bin/gnome-shell as a red D which
(As link) means to be in a IO operation.
How can I get more info in what is the program doing?

For eventual future need, the problem what somehow in the desktop image.
After changing it, the system loads fine.