Samsung Galaxy S10 series comes with Super AMOLED Dynamic display that is a perfect package to enjoy high-resolution movies and high-quality games but some of these apps and games may not stretch beyond the camera cutout mark for a full-screen view.
And if you want to go beyond that cutout limit, there's an option that could allow you to check to see if an app can be used in full screen. Although, all apps are set to auto mode but you can force them to go full screen from following settings.
Note: Some app developers may not have optimized apps for full screen mode. If an app doesn't look right in full screen, try choosing Auto instead.