My 2021 Silverado HC has the 6.2L / 10spd combo and no AFM and no stop/start. Coming from a 2014 Sierra Denali with 5.3L 6spd, with AFM. This new one is incredible. Instant power and the drivetrain feels so much more solid and stable.
When looking at the new ones, the 6.2 window sticker shows better fuel economy than the 5.3... but I am definitely getting a little worse than the old truck did. Not much worse, but a little. I'm pretty sure it's because my new shoes are heavier than before... I can't seem to stay off that gas pedal.