Probably9857 Detoxwz Sounds like you tried to use the installer for stable releases. The Pixel 10 only has experimental support so far. You can install at https://staging.grapheneos.org/install/web, or wait for a stable release if experimental is not for you.
Suchy I successfully flashed GrapheneOS around 2hrs ago on mustang, are you using the staging site? https://staging.grapheneos.org/releases#devices