This comes with a few complexities

• per-player text evaluation
• knowing when to update the text

But would allow some pretty cool mechanics like

• in-world timers
• completion markers

I would suggest by simply evaluating the expressions frequently (offset by entity id so they dont all update on the same tick) and if they change update the display. We can change to a fancier notification system if it becomes a performance issue. Entities with no dynamic text can skip the entire refresh cycle