Make sure your pasted text did not show up in your TERMINAL - even if it is not in focus or even if your cursor is in another Panel tab or in the EDITOR. I ultimately discovered, when I changed my Panel focus back to my PowerShell TERMINAL tab, that ALL of the Ctrl-V pasting I had attempted had shown up after my PowerShell prompt!
Then in the reply box at the bottom of this page, do a right click in the box and select Paste. For example, Command-Space bar opens the Spotlight menu, but in another app it might be used to switch between different input methods. It’s possible to have keyboard shortcuts for one app that conflict with another app. Under the main banner, press the button Copy Text To Clipboard. If a keyboard shortcut doesn’t work on Mac. Ctrl-V was not pasting the code I had just Cut or Copied (but right-clicking and choosing Paste was working). While still in Safe Mode, Type about:support in the address bar and press Enter. My Ctrl-V issue was when I was trying to correct my Apex code in the EDITOR pane. The deployment had errors, so in the Panel area (which I have at the bottom of my screen) I had clicked on both the OUTPUT and PROBLEMS tabs, which shifted focus away from my PowerShell TERMINAL tab. I have the Salesforce Extension Pack installed and had right-clicked on a file and run SFDX: Deploy Source to Org.
For future searchers who do not have Vim (or any other extension) installed which is causing the issue, and who might have verified that their keyboard bindings are correct.