I just got a new PC and installed Ubuntu on it, which I'm completely new to (literally installed 3 days ago). I just found out that when I try to either restart or suspend the PC it turns into a black screen that doesn't respond.
I found a lot of similar questions like this or this but they seem to only focus on suspend and my problem seems to also be when I restart, so I wasn't sure if they are related. I tried following the second link and ran sudo ubuntu-drivers autoinstall && apt install gnome-screensaver but that didn't seem help.
As I'm completely new in this community I'm not sure what details to add, but my CPU is
AMD Ryzen 9 5900X 12-Core 3.7GHz and GPU Nvidia GeForce RTX™ 3090. When I go to software & updates / additional drivers it seems like it's on nvidia-driver-470 (proprietary, tested). I tried switching to nvidia-driver-470 (proprietary), to nvidia-driver-460 (proprietary), or to X.Org server, but nothing worked.
Running nvidia-smi I get:
NVIDIA-SMI 470.86 Driver Version: 470.86 CUDA Version: 11.4
Please do let me know if there is any other information needed to solve this.
