Just FYI, I have a 2017 Sierra Denali with 6.2L engine.
I had shake/shudder issues at low and high speeds. Felt like I would randomly hit a rumble strip, even on smooth pavement.
The issue?
Transmission fluid.
That's right, took it to the dealership, they verified it by a ride with the service manager. They flushed 3x and filled with a new fluid that takes the shudder/shake away.
Been riding smooth ever since.
I hope this helps.
https://ww7.oemdtc.com/8737/shake-and-or-shudder-during-light-throttle-acceleration-between-25-and-80-mph-40-and-128-km-h-at-a-steady-state-2015-2018-cadillac-chevrolet-gmc