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).

[0]: https://support.apple.com/en-us/HT212757

[1]: https://support.apple.com/en-us/HT210380

[2]: https://panic.com/prompt/