There is another option to connect the HK3 using only one constant plus connected to the car's fuse box, and for the HK3 to work correctly: to supply power to the ACC wire, you can use the DRL module (or any other similar module that connects the load when the voltage rises above 13.0 Volts (this happens when we start the engine) and disconnects when the voltage drops below this threshold (this happens when we turn off the ignition)
For example, such a module:
Universal LED Daytime Running Light Automatic ON/OFF Controller Module Box Relay
You can also look for cheaper options, since the current consumed by HK3 on the yellow control wire is very low.
PS: There is a small nuance when using such modules: the voltage drop on the battery to the shutdown threshold does not occur so quickly, after the ignition is turned off, it depends on the state of the battery and its capacity, which can be 30 minutes or more.
Perhaps there are modules from the category of DIY, where the shutdown threshold can be adjusted and thereby set up a faster shutdown.
PPS: Some dashcam had such a function (possibly LUKAS) - the transition from the parking mode to the normal recording mode when the engine was started and with a constant power supply. But an additional set of wires was not used (Hardwire Kit) and 12 Volt power was supplied directly to the dashcam.
If dashcam manufacturers take this into account in their future developments and use a similar technology and an additional module, connecting dash will be much easier (although the cost of the HK itself will increase), but this will also remove the problem of restarting dashcam when starting the engine, when the voltage supplied through the ACC wire is interrupted at the moment starter work
Best wishes!