Hey! I’m pretty young so I’m no expert, but I just wanted to say that your project sounds incredibly cool! Don't let the big studios or complicated software like Unreal get you down focusing on your own story, characters, and fictional weapons sounds like way more fun anyway. Since 3D software is too expensive, you should definitely check out Blender, it's 100% free and you can use your 3D skills to help you sketch your 2D drawings. For growing your audience, Substack can be really slow, so maybe try sharing your art and lore on Tumblr or Bluesky, because the worldbuilding and animal art communities there are super active and nice. Take your time, don't rush, and keep drawing what you love!