Did you make a game engine? I was in game development for 15 years, and making engines is always fun and worked out well for projects I worked on.
My advice would be not to try to make THE game engine. Making a game with its own engine usually works out OK, if team has expertise, of course.
Like Unity or Unreal, don't try to replicate those, creating generic 3D engine for every game. You don't need to. But it is easy to make 2.5D game with its own engine which would absolutely reck "big guys" in performance and simplicity of use.
My advice would be not to try to make THE game engine. Making a game with its own engine usually works out OK, if team has expertise, of course.
Like Unity or Unreal, don't try to replicate those, creating generic 3D engine for every game. You don't need to. But it is easy to make 2.5D game with its own engine which would absolutely reck "big guys" in performance and simplicity of use.