macOS: follow mouse focus on all windows

Use this gem: yabai.
If you just want the follow focus behavior, you don't even need to disable System Integrity Protection. Just use:

> vi ~/.yabairc
yabai -m config focus_follows_mouse autofocus

And then

> chmod +x ~/.yabairc
> brew services start yabai

macOS: how to move or delete backward in iTerm2

Source: With iTerm2 on Mac, how to delete forward a word from cursor on command-line?