Transmission Sensor problems of the 2020 Chevrolet Silverado 1500

In may I purchases a 2020 silverado. On December 05th, 2020. I was driving on the interstate heading home from my son's football game . The "service brake system" message displayed on the vehicle's dashboard. Braking became sluggish and stiff. I initial thought the brake fluid had had leaked out. The vehicle maintained power to all other systems. Once home I checked the engine bay and brake calibers and found them to be intact. At this time the vehicle has 12,400 miles. After a initial assessment, was informed that it was determined to be a "computer glitch" that was effecting the transmission and brake sensors. The brake module was replaced and transmission "software" was updated. This was completed on December 09th, 2020. Upon completion the techs conducting a "drive test", at which time the warning appeared again. My vehicle remains at the service department, while they "troubleshoot" the problem. Due to the vague responses being provided by the dealership service staff and the lack of an estimated time line for the completion of the repairs. I believe there is a much larger issue that they don't want to reveal.