Samsung
Manage Full Screen App Display auf Samsung
Samsung phones render most apps across the entire display by default. This works fine for apps built for the current aspect ratio, but older or poorly updated apps can end up with stretched icons, cut-off buttons, or a zoomed-in layout that hides part of the interface.
You cannot turn off full screen rendering for the whole system. Samsung only lets you set this per app, which is enough to fix the apps that actually cause problems without affecting everything else.
Where to find the setting
Open Settings ➔ Display ➔ Full screen apps. This list shows every installed app that supports the toggle. Switch individual entries on or off depending on whether the app should fill the screen or use the classic 16:9 format.
If an app still looks stretched after turning the toggle off, close it completely from the recent apps list and reopen it. Some apps only apply the new scaling on a fresh launch, not while running in the background.
This setting is mainly useful for older games and business apps that were never updated for taller screens. Apps built with current design guidelines usually look correct either way, so leave those on the default full screen setting.