Android Auto just got the latest update adding a new diagnostic feature that checks if your USB cable/port is not working as expected. If your phone is not connecting to your car, This new diagnostic tool will be able to help pinpoint if the USB connection is where the issue lies (Which is Mostly where the issue lies) The tool is called USB startup diagnostics, which checks the USB cable connection and the cable quality.
Although it’s very hard to see which USB cable has better quality, Only with the right tools will you be able to check if the USB cable quality is up to you or needed? It’s also very tough to know which USB cables have the right specifications to support Android Auto. A lot of phones nowadays come with a USB C to C cable, which not all cars come with, which is why you normally need to use an OTG which Could be causing problems. (This tool will help out)
The tool is available in Android Auto 7.5.121104, If you don’t have that version yet, Just go ahead and update it. And if you already have the app, You can find it under Android Auto settings > Connection help > USB startup diagnostics. Also letting you know the fact that Google normally rolls out features very slowly, so if you are not seeing the new update, you just have to wait for it to become available in your region.