Plenty of apps on Android are allowed to draw over other apps (e.g. Facebook messenger, Lux Auto Brightness). There are also apps that use the accessibility API

Plenty of apps on Android are allowed to draw over other apps (e.g. Facebook messenger, Lux Auto Brightness). There are also apps that use the accessibility APIs to determine what the user is seeing (e.g. LastPass with AppFill enabled). I think both of these features require explicit manual permissions (i.e. having to go to the system settings and whitelist the app) to be enabled. Also Android permission dialogs refuse to pop up if there is an untrusted screen overlay (which meant that my experience with Lux when with other apps' permission dialogs involved either manually disabling the virtual screen brightness adjustment or having it automatically disabled temporarily, which resulted in unpleasant surprises while using the phone at night).