We have that older Mercedes GL450 too. The interesting coincidence is that is also has a 4.7L V8, though a 7-speed transmission. It is a smoother quicker and roomier vehicle, and nicer to drive but more complex to work on, and not as capable offroad...not that we take it past any dirt fireroads/forest service roads.
It is a pleasure to drive though. I do much of the basic maintenance myself. My life is hectic so I hope I have not repeated myself here, but what is interesting is that the engine holds almost 9.5 quarts of oil! It is also low-revving like the 4R so that oil just lasts forever.
Unless something else comes up soon, we have a Rivian SUV on order and it will likely be 2024 before that happens. I could always back out but we do want a larger electric 4WD (or quad motor) type of SUV on the driveway. That is the thought though I still have my eye on a diesel Class C. So much to buy...so little money....