I wonder if there is a limit of number of BT devices on the phone, connected or otherwise?
I use BT to communicate with a number of devices simultaneously and once in a while, I get problems with them failing to connect or dropping out, sometimes mid use. I found that closing down other apps normally clears the problem (I suspect it prevents the app from making a BT connection as I have several apps that can theoretically connect to the devices), although I never close the Tesla app even though it will at that location / point in time have an active/connected BT connection.
3 simultaneous connections seem to be the point of teetering on the edge of stability.