I have used cell phones for many, many years and bluetooth in a number of different cars like Cadillac, Nissan, Lexus, etc, etc. They all basically have pretty big operational problems. Especially when you are using it for more important/complicated stuff like business rather than chatting.

Has a cell phone or automotive engineer EVER used the devices that they design? I honestly don't think they ever do.

My solution. Have more than one cell phone. Or you can get more than one number on your cell phone. Etc. They are so cheap these days that I have found having that type of solution is best.