I've just come out of the Mercedes dealer. I'm also interested in the G-wagon alongside the Grenadier. Unfortunately, I was disappointed.
The dealer clearly told me that sales of the G wagon (all models, including AMG) have been discontinued in Germany. When I asked, he added that "here in Germany we have the wrong government for the car. It's because of the V8 engine". There are still a few demonstration vehicles (but they don't appeal to me personally because of the equipment).
However, he added that I can still buy the G-wagon abroad (including the V8) - he explicitly mentioned Austria. Delivery time approx. 1 year.
A few weeks ago, I met two young women in Stuttgart, each with their new G wagons. They were lucky, as they had ordered just over a year ago. But they also liked the Grenadier. What luck for me.