Follow the owner's manual maintenance guide. Your frequent oil changes, for example, seem excessive -- modern oils and engines are way better than they were in the days of 3.000 mile oil changes. Transmission fluid change? Maybe at 100k.
I also own a 2018 and never had a problem - now have 56,000 miles on it. I follow the recommended service on the car like I did with my 2006 Saab 9-3. That car was still running fine with its service schedule at 191,000. Now the second owner has it with 250,000 miles following the service schedule. I liked Scotty Kilmer as well, but he really is old school on some things and the 3000 mile oil change is one of them. I used to work on cars myself so I always test my mechanic when I move (I use independents) with a problem I know I have with an older car. If they get it right, I use them. If not, I pass until I find someone who identifies the problem correctly. Then I stick with them. That is how I found my current mechanic when I moved to CT with my Saab many years ago.Well, our 2018 Envision Premium I is coming up on the year 4 anniversary, May 25th, and Bumper to Bumper warranty expiration, we have about 44,500 miles in total. Truth be told the car has been trouble free and I am still very happy with the vehicle. We just had it in for an oil change, I change it every 3,000 miles or 3 months since this is one of the most critical care items you can do for a car. All it needed additional was an air cleaner and cabin filter which were both original.
I listen to Scotty Kilmer on YouTube all the time and he recommends fluid changes to the transmission and differentials but I am hesitant to have the dealer do it. I had an ’05 Jeep Liberty that they insisted (Chrysler dealer) I change the transmission fluid on at 40k. I agreed and the idiot service man drained the fluid, forgot to fill it and took it out for a test drive. I only knew because I was sitting in front of the service garage when he returned with it banging, lurching forward and smoking. They had the gall to fill it and tell me it was good to go. I went crazy on the owner and they agreed to a rebuild which they did but the car was not the same. This is how I got my first GM and ’07 Equinox then a ’14 then the Chevy Buick dealer talked me into the Envision. I ramble on all this as I wish I could find a really good mechanic I can trust to do this type of work since my confidence in dealer service bay personnel is limited. Especially since our mom-and-pop Chevy Buick dealer has been bought up and integrated into a multi dealer conglomerate. Big is not always better.
Anyways the car has been the best I have ever owned and from the looks of the new and the reviews I have read the new versions are far superior to the old. So at least something to look forward to.