No, all of the computer stuff will not be wiped clean. Think about it, Chevy does not require reprogramming of the car when the battery is installed originally or replaced.
First, Chevy took the safest way out and said to disconnect the negative cable. Since Chevy does not provide dinghy towing supplemental braking systems they did not address that need.
It is completely acceptable
technically to disconnect the positive terminal instead, all wires. It does not matter which post is disconnected from a functionality standpoint, as long as the work is done in a safe manner.
There are permanently-installed battery disconnect switches that can work when installed on the positive post, both manual switches and electrically-operated switches.
If I had one of these vehicles I would install the disconnect switch on the positive post. I would remove my motorhome charge line from wherever the vehicle end is connected and put that wire on the positive post of the battery disconnect switch. Disconnect switches usually have a way to do that and that directly connects the motorhome charge line to the car's battery (and the negative cable is still connected so it will charge).
If I had an electrically-powered supplemental braking system, either permanent or removable, I would rewire it so that it got power directly from the battery. The relocated motorhome charge line will keep the car's battery charged up.
Whether the car power brakes are working or not usually is irrelevant. Contact the manufacturer of your supplemental braking system for their guidance. You will not be the first person to call them because several vehicles require that the battery be disconnected prior to dinghy towing.
The more annoying part of having to disconnect the battery is that the power door locks and key fob will no longer work. Plus, you need to get inside the car to open the hood to reconnect the battery (usually). So you either leave the car unlocked or you resort to using the key inside the fob.
One person installed a Roadmaster remote disconnect system and put the button inside the wheel well, outside of the car. He pushes the button to disconnect the battery after the car is locked and pushes the button again to connect the battery to unlock the car. That can work but I'd be installing a weatherproof pushbutton myself. And I'd pick a location where I was absolutely certain a rock or road spray or snow or anything else could never accidentally push the button. See this link:
https://www.roadmasterinc.com/battery-disconnect-w-switch/
Hope this helps.