In short: JoiPlay (main app) + Unity Plugin (separate app) + Your Unity game folder = Works
: Check the developer's page (e.g., itch.io or Patreon) to see if a native Android version (APK) is available. Native versions are built directly in Unity for Android and provide the best performance. Remote Play unity+plugin+for+joiplay+work
These are optional but recommended for full compatibility with multi-engine titles. In short: JoiPlay (main app) + Unity Plugin