Stats app is iOS watch app. There is also one called Tesla remote.
BUT - note that the car needs to be connected to cellular, the Tesla servers need to be working, and the watch needs to be connected (via cellular or through the phone). The watch does not talk directly to the car. Usually it will work, sometimes it may not.
I’d suggest the key fob, an arm pouch, or the acetone idea.
Edit to add - and be sure to turn off Bluetooth on the phone locked in the car or the car will stay unlocked. And that might keep the watch from having a data connection.