drhowarddrfine points you to the link for upgrading the system.
The Nvidia card will depend upon a few things. Assuming you have packages set to latest, or even if you don't. Firstly, if you have ZFS (I know you said no guessing, but you aren't giving us some needed info, so we have to), before upgrade, use bectrl to make a backup boot environment. Then if it goes wrong, you can boot into the environment that worked. See my
https://srobb.net/fbsdbe.html which tells you how to do that.
Now, with the Nvidia, it will depend upon your card. Check if your card is supported at
https://us.download.nvidia.com/XFree86/FreeBSD-x86_64/595.58.03/README/supportedchips.html. Note that there are cards marked as Current, and further down the page cards marked as legacy. (Just search for the word legacy on the page). Then you can upgrade it with pkg, but depending on how current the packages are, it might not work. If it doesn't work, I upgrade ports with gitup so that I have the most recent ports, then I use portmaster to install nvidia-drm-kmod and nvidia-drm-66-kmod (in my case, I have an older card, so I actually install the nvidia-drm-66-kmod-580 and nvidia-drm-kmod-580.) In my experience, though I don't guarantee it for anyone else, this (the installing from ports) has always fixed it if was having problems. I should probably put up a page on it, as I've written this explanation so often. Installing these ports will also update any nvidia-driver that needs to be updating.
So, the list of commands is at the link
drhowarddrfine provided. Any Nvdiai drivers are separate, and hopefully, only need pkg update and pkg upgrade to work. If not, my experience has been that it can be fixed using the ports as described above.