Proxmox freezing with Kernel Panic.
This Kernel Panic seems to coincide with IO load.
Navigate to the specific VM causing the issue.
NOTE: As the Kernel Panic seems to coincide with IO load, another option is to try disabling io_uring.
Edit /etc/apt/sources.list, and add in
deb http://ftp.de.debian.org/debian bullseye main non-free
Install the AMD Microcode:
apt update
apt install amd64-microcode
Reboot.