Yes, collision detection in parking mode is also handled by the G-sensor. To help reduce power consumption when your car is off, we recommend enabling Quick Start Collision Detection.I'm having the same version as you do. The video was filmed with an older version of the front camera, which I now updated.
But the menus should be still the same.
The menu in Video Settings - G-Sensor settings should apply to recording while driving only.
The sensitivity of the Parking Mode is set in Video Settings - Parking Mode when Collision detection is selected.
I believe this is the one of all modes, which consumes least energy from battery.
In addition, there is an additional setting below Parking Mode, in German Video Einstellungen - Parkraumüberwachungseinstellungen (no clue what it might be in English) to set collision detection sensitivity to a quick start or a power saving mode. The cam will take longer to start up in latter, however.
What puzzles me is the rear camera version, which is EEE071 for me as well, but the Vantrue website lists a version RC09_VT-EEE281 as initial version for the rear camera. https://www.vantrue.com/de/pages/s1promax-manual-firmware If this could be clarified?
As for firmware, the latest version for the S1 Pro Max is S1PM_VT-EEI121. Your unit is already on the latest version. You can download the latest rear camera firmware through this link https://www.vantrue.com/pages/s1promax-manual-firmware