Refer to ABL and accuracy, which probe to choose? for a bit of discussion on this topic
Using this port is fine. It does not matter which of the temperature ports on your board you are using for the bed and / or extruder. All that matters is that the electrical connection and the pin in the printer.cfg are matching.
So if you have configured the sensor_pin of the bed to be PB1 then you need to connect your bed’s thermistor to THB