APVoid I call BS on the Web Installer being easy. I have tried a chrome book with plenty of storage space, and desktop, Three different browsers, 4 different cables and I still get stuck at different spots in the install.
I'm sorry to hear it hasn't worked out so far. But the GrapheneOS web installer works pretty reliably once the necessary ingredients are in place. The cable matters; the browser configuration and browser release matter; etc.
One thing you could try is Google's browser-based flash tool. If that gets stuck, then there is some hardware/software barrier that will likely also preclude the GrapheneOS tool from working.