This is the best answer here. The green bottle of Turtle Wax Hybrid is the best bang for the buck in car detailing. I fell down this rabbit hole of detailing products and always come back to this stuff. It's so easy to use and top off, and provides the best protection.
Seek back and volume down will get you speaker test and other sync 4 diagnostics. I too am wondering what the button combo is for the engineering mode in the gauges.
I believe the current one button press is required by the epa. The vehicle must default to the mode it's tested in so that standards are consistent with end users. To create an exaggerated example, lets say eco mode got 10mpg better than normal mode, the epa couldn't count that eco mode unless...
I haven't figured this out either. Feels kinda pointless to call it my view then not default to it. I still don't like that I have to press one button to see any info other than a speedo.