If you want to both use a power bank and the parking mode, I would recommend you have a look at the power packs sold by
Blackboxmycar.
The picture below is from
Blackboxmycar. There are two wire installation manners available. Let's call the left: Manner 1, the right: Manner 2.
If you wire the power pack with your dashcam according to manner 1, the dashcam will enter the parking mode when the ignition is off. But you have to remove the current HK3 hardwire kit and rewire the HK3 to the power pack.
If you choose manner 2, the dashcam can enter parking mode by detecting no motion detection in 5 mins. But that detection may be not accurate. The parking mode may don't work sometimes. While, in this way, you only need to unplug the HK3 and plug the provided long USB cable that came with the dashcam into the main camera when parking your vehicle on the sideway outside your house.
Considering your demand for parking mode, I would recommend the manner 1.