Oh it's Unreal. I also uses Unreal and you really should look up on how to reduce the package size. Specially the part about excluding the starter assets. My game is 2D but it's still about 800mb if i don't do this and after the download size is a bit less than 80mb and I learned the hard way that people are not interested in downloading very large games.
https://docs.unrealengine.com/4.26/en-US/TestingAndOptimization/PerformanceAndPr...