Omarchy is what did it. Hyprland hands keyboard focus to whatever window the pointer is over, no click, and you stop thinking about it inside a day. Back on macOS I was clicking a window before typing into it again, every single time.
brew install --cask rbstp/tap/heedThat is the whole setup. Grant Accessibility when macOS asks and it runs as a login agent, no Dock icon and no window of its own. A menu bar cube switches it off, ⌃⌘H does the same from the keyboard. macOS 14 or newer, Apple Silicon, MIT.
Knowing when to leave you alone is the whole job#
Following the pointer is the easy part. Almost all of the work went into the moments where focus must not move, because getting those wrong makes the idea unusable rather than merely annoying.
Type a sentence and let the mouse drift over another window. The rest of the sentence stays where you started it. Focus also holds still while a mouse button is down, while a menu or a drag image is on screen, while you are in a password field, and while ⌘ is held for Cmd-Tab. Open a new window and it keeps focus until you actually come to rest somewhere else, so you can walk over to it across two displays without losing it to everything you cross on the way.
It stops sampling when the pointer stops, which is what keeps it off your battery.