If your goal is 3D, then yes, it’s probably best to use another engine.
With regards to 2D games and the respective codebase size: A Dark Room for the Nintendo Switch is made with DragonRuby. The codebase is around 20,000 lines and has ~8 hours of gameplay. 20k lines might not seem like a lot, but implementing the game in C#, C++, or Objective C would have yielded a codebase close to 60k lines easily (Ruby is a very expressive language that lets you do a lot with very little code).