Where does the built in snipping tool save snips by default?

Sounds like maybe your Ctrl key also thinks it's pressed, adding the Ctrl key put it in the clipboard instead if a file...

Where to find screenshots

By default, screenshots save to your desktop with the name ”Screen Shot [date] at [time].png.”

In macOS Mojave or later, you can change the default location of saved screenshots from the Options menu in the Screenshot app. You can also drag the thumbnail to a folder or document.

https://support.apple.com/en-us/HT201361#:~:text=To%20take%20a%20screenshot%2C%20press,it%20to%20edit%20the%20screenshot.

Portion of the screen:

1. To capture a portion of the screen, press Command-Shift-4. A cross-hair cursor will appear and you can click and drag to select the area you wish to capture. When you release the mouse button, the screen shot will be automatically saved as a PNG file on your desktop following the same naming convention as explained on the first tip above.
2. To copy a portion of the screen to the clipboard, press Command-Control-Shift-4. A cross-hair cursor will appear and you can click and drag to select the area you wish to capture. When you release the mouse button, you can paste the screen shot to another application.

https://www.itg.ias.edu/content/keyboard-shortcuts-capture-screen-shot-mac-os-x

Any luck yet?