Continuing the discussion from Plex HW acceleration in LXC container - anyone with success?:
Hude shout out to constiens for the great tutorial!
Been using this same info for 2+ years to get NVIDIA GPU (1660 Super still going strong!) Hardware acceleration to work with Plex Server running as a container inside of Proxmox 7.3.
Quick note as many others have mentioned in the threat – all newer versions of Proxmox require lxc.cgroup.devices.allow commands to be changed to lxc.cgroup2.devices.allow
Once all steps above are good to go and your conf files are set to pass correct devices you will still need to do some installs every time Proxmox kernel header update is released.
Dropping a quick script below, again very simple and I am sure others can create better, this just saves a few extra minute of getting HW acceleration back up and running after a kernel update 
Please remember to update the Nvidia driver URL & driver file name in below script once you find an Nvidia Driver that works best for you!
Update Script on PVE
#!/bin/bash
touch /opt/nvidia
cd /opt/nvidia
rm NVIDIA*
#Stable for me
wget https://us.download.nvidia.com/XFree86/Linux-x86_64/525.60.11/NVIDIA-Linux-x86_64-525.60.11.run
sudo apt-get install sudo pve-headers-$(uname -r)
chmod +x /opt/nvidia/NVIDIA-Linux-x86_64-525.60.11.run
/opt/nvidia/NVIDIA-Linux-x86_64-525.60.11.run --no-questions --ui=none
rm /opt/nvidia/nvidia-persistenced -r
cd /opt/nvidia
git clone https://github.com/NVIDIA/nvidia-persistenced.git
/opt/nvidia/nvidia-persistenced/init/install.sh
rm /opt/nvidia/nvidia-patch -r
cd /opt/nvidia
git clone https://github.com/keylase/nvidia-patch.git
cd nvidia-patch
./patch.sh
Update Script on Plex Container
#!/bin/bash
touch /opt/nvidia
cd /opt/nvidia
rm NVIDIA*
wget https://us.download.nvidia.com/XFree86/Linux-x86_64/525.60.11/NVIDIA-Linux-x86_64-525.60.11.run
chmod +x NVIDIA-Linux-x86_64-525.60.11.run
/opt/nvidia/NVIDIA-Linux-x86_64-525.60.11.run --no-kernel-module
