I don't know exactly what the 720 can do.
If that device can play music wireless over your car radio, there must be a small FM transmitter in it.
This is completely separate from the Bluetooth which in principle is also a very small transmitter but it can work duplex, that is, send but also receive and that is exactly what you need with your phone.
The FM transmitter is one-way traffic. simplex.
Your RDS-TMC is just as much a receiver as your radio, simplex and only receives information, the place where you are at that moment is then calculated by your navigation and compared with that information from the RDS-TMC.
But what is most interesting now is the Bluetooth.
You can't feel it, you can't smell it, just measure it.
I can't measure it either because my frequency counter does not go higher than 2.8 GHz, but I can hear whether my Rider v2 works by pairing it with a pair of Bluetooth earphones or headphones.
Isn't there a menu icon where you can turn Bluetooth on or off?
On my GO 950 I have that choice of Bluetooth preferences and then the choice of on or off, hands-free on or connect to Bluetooth device.
As soon as I click on, I am connected to my smartphone.
On the GO 950 I use 9,541 but is it possible that your Navcore does not support Bluetooth?