[Idea/Mod in progress] Is this possible?

Added a new thread with appropriate tags in the title (thinking I could delete this after). Please remove this thread. Sorry


Hey everyone. I'm fairly new to modding and I'm wondering the possibilities of an idea that I have.
So far I've done the basics. Make new ore, armor, some weapons, sprites. You know, all the easy stuff. I want to make this mod for post-hardmode. After hearing that there would be no more PC updates, I've turned to modding to make my own.

My idea is to expand the game into the sky. I really liked the floating islands and thought that there should be more above ground. I want to make land across the whole sky above the floating islands. My question is how would I go about generating land in the sky in existing worlds? Or is that even possible? I was thinking to generate it via an item that is crafted or dropped from a boss at the end of hardmode. And I would need to create a new biome that stretches across the whole sky.

Being new to terraria modding, I don't know how I could go about creating this. Some answers would be greatly appreciated, or help with coding would be even better.

Thank you.

Added a new thread with appropriate tags in the title (thinking I could delete this after). Please remove this thread. Sorry