How to create a hotkey for opening a new iTerm2 window?
This is already built into iTerm2.  See the Hotkeys section in their documentation.

Show/hide all windows with a dedicated, system-wide hotkey
Create a dedicated hotkey window.

In its simplest form, it's a system-wide terminal window that you can open with a hotkey.



You can find these options in Preferences -&gt; Keys
OSXDaily has an excellent write up on this (with pictures)