As with most other things having to do with these trucks I'm apparently living in a magical unicorn kingdom because when MDS kicks in on my Ram it's transparent and seamless with no drone and no lag.
Man I lucked out I have great headlights from the factory, no engine problems using the oil viscosity specified in the manual, no problems with MDS, never killed a Bilstein, haven't had any trouble with my 6 speed transmission or the non preload LSD, I get the same performance and mileage on e10 as on e0.. Truly a miracle how I lucked out on every single thing everyone complains about.
For the eco indicator it can be enabled or disabled in the menu for your dash display, dig around in the config screen and you'll find the option. By all accounts the eco indicator isn't directly related to whether MDS is active, though I expect most of the time they're looking at the same set of conditions.