Regarding voice control and garage door opening, there’s no question that’s a serious potential issue. Amazon mentions it on their site and says you have to consider whether this might be a problem for you.
There are people who have their voice device is placed so that even someone yelling outside will not be recognized by the voice device.
There are some ways to disguise the device name so that you could make it something a stranger wouldn’t know, like “open the gorilla fist,” and for now that’s probably the simplest.
Both Amazon and Google are working on individual voice recognition, so presumably by 2030, and probably well before, you could set it up so that your voice device would only respond to your own voice.
So it’s definitely something to consider now, but from a practical standpoint it’s probably not that big a deal as long as you plan for the possibility.