According to Bethesda, Starfield does not actually support the Intel Arc A770 graphics card. By updating manually updating the drivers, it is possible to at least get Starfield to launch. (According to some other A770 owners, the driver updater built into the Arc software doesn’t do a good job of actually finding the most updated driver, so you MUST go find the driver manually.) In my experience, the game doesn’t run great and isn’t THAT stable, but it will at least run, unlike when it first first launched.
Below is a YouTube showing how to download and install the first version of the driver (126.96.36.19972) that allowed Starfield to launch (for me anyway). The latest version support release of the driver (188.8.131.5200 as of the time of writing) that works even better can be downloaded from Intel here. This driver has NOT went through the full WHQL process (yet), but I’ve never had any issues with Intel’s beta drivers and often the beta releases have allowed things to run several weeks before they are released as fully supported WHQL drivers.