Can I automate turning off an accessory a certain amount of time after it is itself turned on?

Hello kevinfromcarlsbad! While what you're looking for isn't a specific option that's available, you can leave feedback about wanting to see that in a future update: Product Feedback

Also, you can control your accessories with Siri, as seen here: Control your home with Siri

That will allow you to tell Siri to turn off your accessory at the time you no longer need it on. While commands can't be scheduled by Siri, this is another option available to you along with automations.

Be well!

Hello kevinfromcarlsbad! Thank you for participating in the Apple Support Communities.

We understand that that you'd like to know if an accessory can be set to turn off a certain amount of time after it's turned on by an automation. We'd like to look into this with you to see how we can help.

When setting up an automation for an accessory for a certain time (sunrise, sunset, time of day), you'll also have the option to select when the accessory turns off by choosing "Turn Off". You'll have the option of selecting how many minutes or hours you want the accessory to be on for.

The article you visited previously has more information: Create scenes and automations with the Home app

Make it a great day!