/usr/bin/nvidia-settings will be available as soon as you install the nvidia proprietary driver. How to do that is explained in several threads in this forum.
The default text size of terminal is too small. How can I increase the default text size so that I don’t need to Ctrl++ every time?
Which terminal ? konsole (KDE), gnome-terminal (Gnome) and Terminal (xfce) have their one configuration. Most other terminals use Xresources. There are many ways to set the size of terminals. At a lower level, you can change xterm default size by editing the file /usr/share/vte/termcap/xterm . I would have to double check if it works in openSUSE. It does on some distros, not all.
The OP does not mean the (start) size of the terminal application, but the size of the characterr inside the terminal window. That can be increased (for Konsole at least) by in of the menus (View, I think) or by Ctrl++.
In konsole you can make a new profile with a greater character size and from then on use that profile (by changing the call in the menu where you start it from). When you need more precise information how to do this, post back. I will then try to recreate this for myself and anser you tomorrow.
I had the same issue shuting down my opensuse install a while ago and the fix was to flash my bios to my motherboards newest version. The original bios flash, the apci tables had been corupted for some reason causing my pc to shutdown but never actually turn off.