If you're on a recent macOS + iPad, there's Universal Control[0] (I use this as a way to have chat/mail on a second monitor). If you don't mind some noticeable latency, you can use it as a second display via Sidecar[1]. Finally, you can do the same thing described in the article with any terminal emulator app and SSHing into the remote system (I've had luck with Prompt[2], which is available as a one-time $15 purchase).