How to get an alert based on the duration of a sensor status?

Here’s my scenario. I have a downstairs bathroom for which, when unoccupied by a human, the door must remain open because the cat’s litter box is in the same room.

I’ve been playing around with Homekit a lot recently, so this seemed like a cool idea to try to use a door sensor for.

I installed the Eve door sensor, and it’s working great. However, it seems that Shortcuts can only be set based on if a sensor detects something, so basically this would only work at the exact moment when the door is shut or when it’s opened.

However, I’d like to set off some kind of alert only if the door remains shut for an hour or longer.

Now, I’ve figured out that I can use the Controller app to set a scene based on a duration of a sensor status, but I’m not sure how I can create a scene that results in some kind of alert. I mean, yeah, I could make some lights red, I guess? But is there some kind of alert that could be set that would be more obvious or direct?

P.S. I’m not looking for solutions like “add a cat door” to your door. This is more of a problem that I’m trying to solve through automation just for fun, to see if it can be done.