I'm not too proud to admit I took the general concept from https://sadservers.com/ and turned it into something I could use for interactive debugging interviews.

I had golden images with some scenarios I wrote myself, and the images automatically shared a tmux session over http so I could follow along without requiring the candidates to screen share.

I did have to ask for IPs so I could ensure the machines were just available to me and the candidate, but it was otherwise pretty seamless!

Though now that https://sadservers.com/ has a paid service it might be worth looking into.