@JW2020, I have recently had a similar situation. I have a 2020 Silverado 3500 SRW with 33,000 miles. I'm from Missouri and we were doing a 10 day trip in Colorado to various places in mid-June. The family and I were pulling our 5th wheel toy hauler and had come over a mountain pass and stopped to take pictures. I left the truck idle because we were only stopping for a few minutes (maybe I should have used the high-idle switch when I stopped).
When I got back to my truck after the few minutes of being stopped, there was a message on the screen saying to "please continue driving...". It apparently tried to do a regen while sitting there idling. Of course we were going DOWN the mountain so we weren't getting super high on the RPM's. My truck also gave the message about reduced engine power. I have a bluetooth OBD reader and use the "Torque" app (on Android) to read engine codes. I only had a single code which was P2463 (Diesel Particulate Filter Restriction - Soot Accumulation). We had about an hour to complete our drive to get to the campsite and as we drove to our campsite, the truck and trailer started tugging almost as if I was having transmission issues which scared the hell out of me. I believe it was from the reduced engine power whenever I would hit the pedal.
I called a local dealership in Alamosa, CO and they were all booked up. We decided we'd hit the Sand Dunes National Park as planned in the morning and head out a day early so that we could move to our next destination and get the truck looked at by a dealership that said they could squeeze me in up in Gunnison, CO. Well, the next morning we are heading back to the camper after visiting the sand dunes and about 1.5 miles away from our campground when the truck lost all power. The truck would start and idle, but then shut off after about 5 seconds. I started getting a 2nd code at that time which was a P2453 (Diesel Particulate Filter Differential Pressure Sensor Circuit Range/Performance). Had to have the truck towed to the local shop that was all booked up (on June 15) and I just got the call the other day that my truck is done. My truck and trailer have been sitting in two different spots in Colorado for nearly a month while the truck is fixed.
GM Assistance really saved the day for us because they said "as long as the fix is covered by the warranty" they'll pay for the tow to the next location ($1,200 - for 3 hours away).
To top it all off, last year (2020) in June I had owned the truck for a month and it had around 13,000 miles (it was used) and the entire exhaust needed replaced because of a similar DPF issue but it didn't make the truck stop running or reduce the engine power.
I'm heading to Mexico for a vacation this weekend and picking my truck/trailer up next weekend in a "quick" 30+ hour road trip...wish me good luck.