As reported on Google’s product forums, the Android 10 installation seems to be stuck at the boot screen for anywhere between 30 minutes to six hours.

How long does it take to update to Android 10?

System updates usually take around 20-30 minutes, depending on how major they are. It shouldn’t take hours. after the software update loading screen it went into system recovery.

Will my phone get Android 10 update?

Android 10 started rolling out from 3 September to all Pixel phones. Go to Settings > System > System Update to check for the update.