I've been having problems with my phone key. I have an Android Samsung Galaxy SG20+5g. It always connects at home but when out an about, it never unlocks the car. When it doesn't work, I just have to turn on the phone - not open the app or even unlock it or anything - to get it to work. Today, I dug into the phone settings and found the Tesla app defaults to optimize for battery meaning the OS can put it to sleep. Turning that off seems to have fixed my problem. If you have an Android phone and are having similar issues, give this a try.