Lucky me, had the lifter issue on cylinder #5 and resulted in a bent rod on #4. Dealership replaced both banks of lifters and rod with a complete inspection of the rest. Took about 2 weeks to get back but less than 48 hours later had to get towed back in due to code P0300. So now we're looking at a bad coil or injectors on a 2020 1500 Sierra with less than 25,000 miles.
And the kicker is that they don't think GMC will cover the injectors under the warranty.