Most of the shortcuts in your list work, you just need to read a little bit more carefully the articles you linked
The first method is also the best known and it works in all versions of Windows: on your keyboard, press the PrtScn (Print Screen) key or CTRL+PrtScn keys. Windows creates a screenshot of the whole screen and saves it to the clipboard. It is not stored as a file on your hard drive. Then, open an image editing program like Paint and paste the picture from the clipboard. Then, you can save it as a file and even do some basic editing.
To Save Your Screenshot as a File
Press the “Windows logo key+PrtScn.” If you’re using a tablet, press the “Windows logo button+volume down button.” On some laptops and other devices, you may need to press the “Windows logo key+Ctrl+PrtScn” or “Windows logo key+Fn+PrtScn” keys instead. Check your laptop’s manual for more information.
The screen will dim for a moment, and you will see the screenshot appear as a file in a folder entitled “Screenshots”, inside your default “Pictures” folder. The screenshot is automatically labeled with a number.
In short, PrintScreen combinations without Windows stores the image in the clipboard, otherwise it'll be stored in the pictures library and not your desktop with Windows+PrtScn. Or just use Windows+Shift+S and you'll have various choices of copying the screenshot to clipboard, editing or saving it as a new file