Blender no longer has a game engine.
You can animate actions in Blender, then export the animation into Unity, then have the animation play with a button press or joystick movement. However this doesn’t solve the difference with the render engine.
The answer I think you are looking for is with the texture maps. To have amazing looking characters in Unity, you need to have a good quality game ready model, and probably at least 4k texture maps, preferably 8k.
The model will need to be a low poly mesh with normals maps baked from a high poly (sculpt)version, normal map again at least 4k.
There is a lot to consider, and work involved, in producing good quality game ready models.
