If you didn’t get this issue, here is how I managed to get this GPU set up mostly properly, pretty much the best it’s been running on any distro I tried.
To sum it up. This GPU only supports nvidia-390xx drivers, and no later.
nouveau also has no official support for the 820m so it doesn’t perform well.
Installed a package nvidia-inst and ran
nvidia-inst -t --series 390 --bumblebee --32
This checked the setup, and listed out a series of commands, most of which you should perform as root, except yay.
In the end, check the kernel parameters where nvidia-drm.modeset=1 was added, if there is nomodeset also there from a previous setup. It was keeping my system in terminal only mode, causing a black screen. I use grub so removing it from /etc/default/grub and running sudo grub-mkconfig -o /boot/grub/grub.cfg fixed it.
Steam had the same crashing issue, but now seems to run with no problem.