can you make any project with this?
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).
What the heck are you talking about? I work with Ruby everyday, I receive a lot of offers, ...some times several a day. If you use Github, Shopify, Stripe and thousands of other smaller sites, you use a Ruby powered site. ... I guess I'm feeding trolls again :/