My phone is not receiving iOS updates.

This:

shows you are running on the battery alone with a low charge. That may prevent the phone from accessing the update servers.

Connect your phone to the charger and try again. As the others said, you are probably maxed out, but the error message should not show unless something else is at play.

Your iPhone 8 is at the maximum iOS it can run and cannot be further updated.

You can update an iPhone 8 Plus to the latest release of iOS 16 - currently iOS 16.7.10. You cannot update an iPhone 8 Plus to iOS 17 or later.

About iOS 16 Updates - Apple Support

I do not know why you are having problems updating to iOS 16.7.10, but we are fellow users and cannot fix your phone for you.

You may find the following to be useful.

Updating iOS: common issues and solutions - Apple Community