Is this not an oil/liquid cooler? Looks like it to me, at least, and I'm also assuming that it is similar to what I THINK I have in my 2018. Set me straight if I'm wrong. But if so, then air flow is irrelevant. And also if so, then I don't see how trans cooling with a properly sized liquid/liquid cooler can be significantly improved on with oil/air cooler. Oil/air coolers are WAY less efficient in the first place, because vis of the cooled oil increases and not only insulates the flow from the outside in, AND the cooler, more viscous oil also resists that flow. And, since your radiator (like almost all modern radiators) is so oversized that it's thermostat usually only lets a fraction of the coolant flow into the engine, under all but the most punishing conditions, it has beaucoup spare capacity, for both the engine and the transmission. Put another way, IF the liquid/liquid trans cooler is properly sized (and I'll bet our stock one is), then by the time trans temp gets too high, we need to be unloading the drive train any how, by slowing down, pulling over, etc.
Also, I just hate more mechanical complexity and leak points. I'd ask Chevy, and heed their advice.....