iTerm2 でフルスクリーンで起動しているアプリにターミナルを重ねる

Preferences > General > Window > Native full screen windows

disable

https://gyazo.com/3d0434e181afba8f50eb35e8de961609

Preferences > Profiles > Window > Settings for New Windows

Style

Fullscreen

Screen

Screen with Cursor

Spaces

All Spaces

https://gyazo.com/dadf59a3905b48ad6c3e237122b33c58

Preferences > Profiles > Keys > A hotkey opens a dedicated window this profile.

Enable

https://gyazo.com/dddb50983b7bccd84f21738515e55b4f

Preferences > Profiles > Keys > Configure Hotkey Window

Floating window

Enable

https://gyazo.com/0746763db71b017462f4276ebab9d15e

参考