The Plex deep links will automatically resume.
TV shows are tricky. For that, I use the Plex integration of Home Assistant to play a random episode. It's supposed to be super powerful, but I haven't got it to work reliably yet (which is why I didn't focus on TV Shows in the blog post).
And I'm wondering if these could be adjusted to have the card be "inserted" and turn off when the card is removed?
I have some nfc tags sitting around but they are much thicker. Maybe I can 3d print something those tags can click into and make like a mini vhs player for them
For audiobook that has been done: https://us.tonies.com/ The moment you lift the figure it stops playing and will resume, when you put it back. Nice concept for little kids and it went really well here in Germany. You will find a Toni box in most middle/upper class households. They are magnetic.