Ohh yeah ... I see it ... "Automatic Stop/Start with disable". So it's gonna be the "one-timer" solution that you'll have to press every time you get in the vehicle.Go online to the Chevrolet dealer of your choice and pull up a 2020 Blazer either on the lot or "In Transit".
Click on a window sticker.
Look on the page under Standard Equipment, then Mechanical.
It lists the Stop/Start deactivate switch mounted on the center console for the ignition cycle.
Well .. that's so close to being "permanent" that it shouldn't take much to *make* it permanent, right? Probably just use some variant of "VictorVDC's" solution.