Hi expee,
I’ve checked the current consumption of the JSN SR04T-2.0
And with 8mA it is ok to power it from any Core Module GPIO. So connect the power of the ultasound sensor to for example P7 (P8 & P9 are used for sensor signals).
Then you enable this GPIO to logic 1 before you call bc_hc_sr04_measure and then you set GPIO to logic 0 in event handler to disable sensor.
It is possible that the sensor will need some time/delay after power-up and before the measurement is started. Let me know if you need any further help.
Martin