Also just switched to a Pixel 3 (XL) which solved all of the bluetooth issues I was having with various Samsung devices. Car instantly unlocks with no failures and I maintain a stable audio connection for calls/media when driving...FINALLY!
However, I have been having terrible 4G/3G/1X phone reception in the charging cubby. I've used multiple devices and all of them start cutting out mid conversation. If I pull the phone out and hold it around the center console, reception returns, but as soon as I move it back to the charger, signal drops considerably. We've been using a cheap ebay Qi charger and I'm hoping it's the culprit. Just pulled it and replaced with OEM standard plug dock. Fingers crossed there isn't something else in that area causing signal interference.
Any search for cell reception on Model 3 returns people talking about the car's LTE ATT connection...not the mobile phone of the occupants.