You actually do have a clue as to where to begin and that was to start this thread on this forum. :xyxthumbs:
From experience, most car manufacturers will make recommendations assuming the unwashed masses, (that's you and I), are also the lowest common denominators of the world, in other words, none of us are the sharpest tools in the shed.
The dealerships for these manufactures are also the primary culprits for doing the most damage to their own brand or marque of car.
Go figure?
Here's your pictures, cool looking car
GYEON makes very high quality product and offers matte specific ceramic coatings. Take a look at what they offer both for a coating and maintenance.
If I were in your shoes, I would also be VERY PRO-ACTIVE in educating the owners about how to take care of coated matte paint. Most people know squat about their car in general, very little about car paint and even less about matte paint.
Feel free to share the link to my article here.
How to safely wash a ceramic coated car by Mike Phillips - Traditional Hose & Bucket Approach
I share this with all my customers as well as explain to them sternly that they CANNOT take their car to any type of mechanical car wash. Their options are,
1: Wash it themselves using the technique I share above.
2: Hire a pro detailer to wash their car for them on a regular schedule.
3: Take the car to a respected touchless wash.
Any other option will lead to marring, swirls, scratches or worse.
I cover all this in my car detailing classes, I wish you could have attended the one you wanted to attend a few months ago.