Longtime former Spectacle and now Rectangle user here. An ancillary issue I'm curious how people deal with is efficiently getting the mouse pointer from one display to another. When working with two apps on two screens, constantly dragging the mouse all the way across one display to the next and back is tedious. I found Keymou [1] years ago to solve this with hotkeys but am wondering if there are other tricks or apps to help.
1. https://manytricks.com/keymou/