There is quite a few new cars that seem to be a royal pain to get working with dashcams, and not least parking guard, some have in desperation gone as far as connecting directly to the car battery, and as i understand even that have not been enough for some.
I can install a dashcam in my own car in 30 minutes ( conventional setup ) but doing the same in my friends fairly old Mercedes estate, well it took me hours and in the end i used a fuse i had dismissed several times earlier as a always on fuse.
And i was just hard wiring one +12 V for neatness of install not parking guard.
@jokiin have a tech at hand that maybe can come up with alternatives as to which fuses to tap into.
Sort of related, having been given a SG9663DR to test, i ended up as a few others having the camera date / time default when my car had been parked around 20 hours.
Also some times the camera did not boot on the first drive of the day.
Tried a few fuses and ground points with no change, so i bit the bullet and got a new battery to replace the 2012 battery in my little Suzuki car, and since that day i have been clear of that issue.
Just go to prove, that some times all ones educations and DIY skills can get put to the test, and you end up sitting staring with a dazed look at something scratching your head.