I recently flashed GrapheneOS on a Pixel for a friend. I was very surprised that you can do this entire process from the browser using WebUSB - the only downside being that it required me to launch Chromium.
Web USB and Web Bluetooth are amazing. I've used the former for the excellent Web MiniDisc [1], and the latter to flash custom firmware [2] on cheap Xiaomi Bluetooth LE thermometer/hygrometer devices that Home Assistant can pick up.
Truly opening new possibilities, since I wouldn't have been comfortable running some sketchy script or local binary.
[1] https://web.minidisc.wiki/ [2] https://github.com/pvvx/ATC_MiThermometer
You can flash GrapheneOS on a Pixel from another pixel, no pc required at all. I've done it several times, this is what sold me on the utility of WebUSB. You can use GOS' own distribution of chromium, Vanadium, if you have a GOS device and you want to avoid Chrome.