As I've posted in a different topic, I have success using open/close, even shut. with devices and scenes, but no success with programs. According to UD, open and close should work with all.
Teken,
Securely controlling garage door using voice commands depends on the situation. Our home is gated, the garages are 70 feet from and 20 feet above the street. I'm comfortable using voice commands. But, I won't use them for the entry gates nor any doors.
Regarding my comment above, I use scenes to control the garage doors, so it really doesn't matter if we say open or close, each command reverses the current position of the door. OTOH, I have a program that closes the garage doors, but can't open them. I have to tell Alexa to turn the program On.