Firstly go to Settings , tap "display" and scroll down to "fullscreen apps" then go through all the apps and change them from Auto to Fullscreen, it will fix some but not all apps have been updated by developers to work around the cutouts yet and some might never be because they're lazy. It was the same when the IPhone X came out it took months because the notch was something new , now we have Infinity O. So it'll be the same. Might seem obvious but have you gone to Settings - Edge screen - edge lighting and toggled on Edge lighting , always show , gone into edge lighting style and set the width to max and transparency to low. Then go down to manage notifications and toggle all available apps. Hope this helped.
