There are plenty of options. Really depends on how much you're willing to commit to the cause.
I guess I mainly interested in disabling V4.
If this is all you're looking to do then the simple easy plug & play reversable option for you would be the Range AFM Disabler device.
Model# RA003 works for the 2020 GM 6.2 SUV platform.
$250 +/-
Our patented technology is the only product that will disable Active and Dynamic Fuel Management without reprogramming the factory ECU. Full power delivery all the time without factory warranty concerns. *It is suggested the device be unplugged if the vehicle is not being driven daily or left...
www.rangetechnology.com
Willing to commit a bit more and spend some time adjusting things like throttle response with some nice added features of adjusting the speedo for different size wheels/tires, etc and still easily reversable. Range Pulsar LT # 22454 works for 2015-2020 GM SUV with either 5.3L or 6.2L
$500 +/-
The 22454 Pulsar LT is a new in-line module for 2014-2018 Chevrolet Silverado 1500 and GMC Sierra 1500 5.3L, and 2015-2020 5.3L/6.2L SUVs, that offers complete adjustability of many features, all from your steering wheel controls. Without modifying your truck's ECM, Pulsar LT offers you the...
www.rangetechnology.com
Full commitment all-in; Get a custom tune from a vendor like Blackbear Performance or a local GM LS/LT performance shop that likely are using an HPTuners software platform. You can meet with them, tell them what you're looking for, and let them take it from there.
This still can be reversible, but more involved to do so than the above 2 options.
Price varies with options; Likely over $500+.