There is no official Unity plugin for JoiPlay. While JoiPlay supports engines like RPG Maker, Ren'Py, and Godot through specific plugins, it does not currently have a native plugin for running Unity-based PC games on Android.
Vector3 movement, and interpreting Unity’s unique API calls.: JoiPlay is an interpreter, not a full Windows emulator. It cannot run games that rely heavily on Windows-specific APIs or complex external dependencies. The Status of Unity Support joiplay unity plugin
Alternative Paths: Players usually have to wait for an official mobile port from the developer or use PC streaming software. Run Unity game app in Android phone | Unity tutorials There is no official Unity plugin for JoiPlay