Check your /etc/apt/sources.list.
It should end with "main non-free contrib non-free-firmware" all the debian.org deb section.
for example:
deb http://ftp.de.debian.org/debian trixie main non-free contrib non-free-firmware
deb...
It's interesting that the memory usage is 101.15% on the pfSense (2.8.0) VM in PVE 9.
On PVE 8, the memory usage was around 70-75%. That was also incorrect, but not over 100%.
The memory balloon is off due to a missing implementation in FreeBSD...