Google has started rolling out a dark theme for the Google Play Store on Android devices running Android 10, and the good news is that it works just as well on Samsung devices running Android Pie and One UI. Google is rolling out the dark theme for many of its proprietary apps gradually to more and more users – it's a server-side switch instead of an update to the apps themselves in most cases, and at least the Google Play Store dark theme is now available for many users rocking a Galaxy device running Android Pie.
What's interesting here is that the Google Play Store follows the Night mode setting on Galaxy devices. Turning Night mode on will enable the dark theme in the Google Play Store and switching it off will revert to a light theme. However, that's only because the Google Play Store is one of the few Google apps that do not have a manual toggle for light and dark themes in their settings. Apps like Gmail will let the user switch between a light and dark theme manually or set the app to follow the system-wide dark mode/Night mode, and it remains to be seen if these apps will follow One UI's Night mode setting on Android Pie.
They technically should, as while Android Pie does not have an official Night mode in stock Android that users can access, it does have a Night mode built into the system code that can be accessed in the hidden developer options menu found in all Android devices. Samsung's Night mode seems to work on this hidden setting, which is why the Google Play Store goes dark when you enable Night mode on a device running Android Pie. Again, we will have to wait and see if Gmail and other such apps with selectable dark mode settings work on Android Pie-powered Galaxy devices or whether it will require them to be on Android 10.
Has the dark theme for the Google Play Store gone active on your Galaxy smartphone or tablet? You can check if it has by simply enabling Night mode from the notification shade and then opening the Play Store app.