You describe that you need to return to Stock Android due to Factory Reset Protection. This is a suitable tool Android Flash Tool. Many other threads on the forum about FRP have hashtag frp.
You ideally want USB debugging, but this tool will use Fastboot mode where USB debugging is not strictly required. There is a risk of difficulties having no USB debugging if one fails to install cleanly in Fastboot mode.
Study carefully how to use the tool before you start.
Pixel 8 have a anti-rollback lock which could brick the phone. You must beware of this in returning to stock (but the tool will hopefully try to protect you). More info in this thread Pixel 8 flashing process - looking for advice