Ok, so I have more information. I rec'd my ATEQ tool which requires me to select my vehicle, and I was able to scan and read the sensor information from my original 18" wheels no problem (433mhz as expected). I could not scan the newer 20" wheels and I had a hunch there might be no sensors. Went to the tire shop, they used their Autel MaxiTPMS scanner, they could not read the sensors either. They broke a sidewall down and verified they do in fact have the tpms sensors:
I googled the part numbers and I can see this is a factory part for 2021 Yukons, Suburbans, and Escalade.
I took my ATEQ tool, selected 2021 for either of those models, then the new sensors trigger and I can scan them. No year earlier, no combination of Sierra or Silverado works either.
I have emailed ATEQ support for ideas, but I'm guessing something significant has changed for these sensors. Two options for relearning:
1) Manual - activate the relearn process from the truck menu and to trigger the sensors in order. I had no luck, I had the truck in relearn mode (two horn beeps), when I trigger the sensor with the tool, I don't get the single horn beep like I should.
2) Auto - I'm not comfortable trying at this time because it programs the ECU with settings for a different vehicle selected in my ATEQ Tool. I'd like to hear from support first. It triggers, loads the sensor ID's by position, and uploads via the ODB port.