To your first comment, personally I don't think it's silly at all to want to simply speak a phrase rather than take out the phone, go to the app, find the control and activate it. This is a pretty usual conversation regarding these voice activated assistants. Several years ago I automated most of my house including of course almost all the lighting. I remember immediately dispensing with the idea that it was cool to take out your phone and control lights from an app. Sure it was an interesting new-tech demo to show how your home is automated, but not very convenient in practice. The useful automation was from scheduled or reactive tasks, like turning on the porch light at dusk, turn on the kitchen room light when someone comes in after dark, turn off most lights when I leave the house but randomize a few for security, things like that.
The slightly later advent of Echo and Google Home type devices allowed much more ad hoc control of lights, fans etc using simple voice requests. It's become my first-choice method over flipping wall switches. You can have typical groups set up ("turn on the evening lights" or "turn off all the lights") and you don't have to interrupt anything youre doing - unless there's so much background noise or other talking that the unit can't isolate your voice (I haven't activated the capability for personalized recognition of my unique voice, which might help with that; so far it's not important enough for me to want the deeper relationship with the AI entity).
But regarding your very good question about timed events (do an action at a certain time, after a certain delay interval and/or for a certain duration):
I'd say that this is about the biggest shortcoming I've experienced so far, and it's very annoying that Alexa (and I think Google devices also) AFAIK cannot do this in a natural way. I suspect there may be some patent issues from legacy automation makers (eg Control4, Honeywell or the like). It's surprisingly hard to find a good discussion/explanation of why such basic capabilities are not supported. You can easily say "remind me to turn off the light in ten minutes" and you'll be correctly prompted, but currently you cannot say "turn off the kitchen light in ten minutes", or "turn on the kitchen light for two minutes" etc.
As a work-around, you can set up a very specific routine
named "Turn on the kitchen light for two minutes" which, in use, performs that very specific action. But then not a similar action with a different light or a different time interval, nor at a specific time of day. An observer might think it understood your time-based request, but it's phony - you'd have to create a incredibly huge number of such specific named routines to have it respond to all variants, and that’s clearly ridiculous.
As yet I have no personal experience with various Tesla app(s) using Alexa, but considering the above I'd expect that you could easily pre-program a few
specific recurring phrase-routines like "warm up the car at 8AM" or "get the car ready in half an hour". But again you'd be limited to the exact time value(s) in your pre-programmed library of routines. More practically, you could simply bypass the voice request method, and create a routine to have it prepare the car every weekday at 8AM with no prompting on your part.
I hope they address this serious timed-action deficiency, but as I said there must be some good explanation known to the insiders. It's one of those things where you search online for a solution to your problem, you quickly find a bunch of other people asking about the same problem, but no good answer.
Here's an article from 2019 that at least acknowledges the problem and talks about new capabilities to address it (but not really IMO).
Amazon adds new wake-up lighting and sleep timer features for Alexa-powered smart lights
