It doesn’t matter how you do it. I often, (when using a public charger), leave the car on so I can see when it estimates it will be full.
i often use DCF, & in the winter leave everything run so it’s warm inside while charging. The car figures it out & begins. You will get the triple horn chirp if leave it running, get out & close the door to hook up the charger.
i use ChargePoint, FLO, & the Petrocan DCFC here in Canada, & it didn’t matter if I left it running.
ome thing with DCFC, you have to connect, then press the START button on the DCFC cabinet. I’ve been in a hurry on a cold day, jumped back in the car, wondered why it wasn’t charging...whats that flashing light on the cabinet, the one that says START...DUH!
with DCFC you can also crank the heater, & the electric supply system will put out as much as the Bolt battery will accept.