there's just this vague recommendation to "turn it off in settings." no link, no toggle, nothing.
had to hunt for the relevant setting in the app(even their settings menu is down under in the list when you tap on your avatar.
image transcription:
a screenshot of Google play store which has a popup that can only be disabled by pressing OK button at the bottom.
the popup contains the following text:
Google is optimising app installs with your help
Google Play makes apps faster to install, open and run based on what people are using most.
The first time that you open an app after installing, Google notes which parts of the app you use. When enough people do this, your apps will install faster.
App install optimisation is automatically turned on, but you can turn it off in settings. Learn more
Not all devices are supported. Building a list of what code is actually run is going to be device dependent, so it only handles popular configurations.
Or, it could be that you're running an older version of the play store, or maybe there's some other reason that it's not using this feature that I don't know about.