The current and best upgrade using Brembo 6 piston calipers from the CTS V carbon ceramic set up with standard pads and standard iron discs is here …
https://ctsvbrakeswap.com/products/gm-truck-suv-6-piston-c6-zr1-caliper-big-brake-bracket-kit
20" minimum rims needed. The issue is that the 16" discs that Centric / Stoptech manufactures for GM are on back order due to COVID related shipping and manufacturing delays. I have not looked into purchasing the same disc as an OEM part from GM # 84263238.
The calipers are massive C6 Corvette ZR1 Monoblock units made by Brembo for the 09-13 ZR-1 Vette with carbon discs. I'm waiting on the discs to come in from Stoptech to install the kit. I already shelled out the $9h for new calipers. I went with this kit because of the massive discs. This kit is essentially a clone of the factory BBK for 2015+ vehicles listed for $2.6K here …
https://www.brembo.com/en/company/news/brembo-and-gm-team-up-on-performance-front-brake-kit
The kit allows standard and less expensive ZR1 mono block calipers to be used with an adapter instead of Brembo's proprietary kit made just for the offset of the GM / Chevy / Cadillac trucks.