Back in 2017, Samsung pushed a ton of its apps over to the Play Store, but now one is making the opposite journey. Samsung has recently updated its Play Store app listing for SoundAssist to warn users that new versions will be distributed through the Galaxy Store.
In case you're unfamiliar, SoundAssistant was pushed to the Play Store back in 2017 to offer extra tools for things like multiple-app audio, separating app audio through specific outputs, and additional granular controls.
We can confirm that the latest version available on the Play Store is several minor revisions behind the latest version at the Galaxy Store (~3.1 vs ~3.3), and the app's description and changelog has been explicitly updated to state that "The new version is distributed through the Galaxy Store" with a link to the Galaxy Store's listing.
If you're a fan of the app, you'll want to make sure you're pulling down updates for it via the Galaxy Store going forward.