Extremely weird issue involving RTX 3060

[cscs]

@LeJeff

mhwd results

In this case then

sudo mhwd -r pci video-nvidia-470xx

Though of course we want to eventually be able to install the proper current one
(ex: sudo mhwd -i pci video-nvidia)

@LeJeff

Machine:
  Type: Laptop Mobo: Micro-Star model: B350 TOMAHAWK (MS-7A34) v: 1.0
    serial: <superuser required> UEFI: American Megatrends v: 1.20
    date: 03/16/2017

Wow, for one thing you have an extremely old BIOS
(with newer hardware)

You should definitely update that.
If my search-foo is correct
https://www.msi.com/Motherboard/B350-TOMAHAWK/support

Note: It appears the MSI updates support what they call “m-flash” which means you can boot it from a USB and update that way. See the documentation at the support page (also with links to videos).

PS. This is not related to your problem, but I notice the system has no SWAP.
That means when the physical RAM as all used the system will lock up.
You have lots of options for SWAP, including a partition, swapfile, etc… but I generally suggest zram these days. ex (continuing the discussion from Awful performance since install):

@cscs

sudo pacman -Syu zram-generator

Then edit the configuration file. (use your preferred editor)

sudo micro /etc/systemd/zram-generator.conf

You want it to look like:

[zram0]
zram-size = ram / 1
compression-algorithm = zstd
swap-priority = 100
fs-type = swap

You may want to ensure zswap is disabled as well. One way is to add to the boot options, at /etc/default/grub the option zswap.enabled=0.
That is to add it to one of the CMD lines so that (Assuming no other options) it would look like:

GRUB_CMDLINE_LINUX="zswap.enabled=0"

Then run

sudo update-grub

And reboot.
You can check the configured swap/zram using

swapon

zramctl