Removing gray bar in kiosk mode Chromium with Puppeteer

Question

I'm using Puppeteer to launch a full screen 'headfull' version of Chromium to control screens around the office with dashboards and the like. We're looking at Puppeteer specifically, as a number of the screens we want to show need a scripted login to access.

Seems like using kiosk mode always leaves a gray bar at the top of the page (example) - presumably where the tab bar and title bar is normally.

Is there any way to expand the viewport to be truly kiosk / full screen? I've tried both appMode true/false to no avail. Also tried specifically setting the viewport to the screen resolution and leaving as 0,0 (using full screen).

My launch code:

const browser = await puppeteer.launch({
   headless: false,
   args: ['--start-fullscreen', '--kiosk', '--disable-infobars', '--disable-session-crashed-bubble', '--noerrdialogs'],
   appMode: true,
});

const page = await browser.newPage();
   await page.setViewport({
   width: 0,
   height: 0,
});

Is it possible or a limitation of Puppeteer / Chromium?