For anyone who might not be aware, Chrome also has the ability to save screenshots from the command line using: chrome --headless --screenshot="path/to/save/screenshot.png" --disable-gpu --window-size=1280,720 " https://www.example.com "
Firefox equivalent: firefox -screenshot file.png https://example.com --window-size=1280,720 A bit annoyingly, it won't work if you have Firefox already open.
now try and go ahead how you could isolate these instances so they cannot see each other. this leads into a rabbit hole of bad design.