This is a wonderful deep dive into your project. I'm early days on creating pixel art style procedural art systems, and this gives me plenty to think about.
That's not open source though... I would like to release this with a permissive license for humans only. From what I've read, the jury is still out on having your license copied left to the AI companies even when they're training on your information.
I too have gone with fountain pens as my every day pen. There's zero waste with a bottle of ink and a cartridge. I find that the variety of inks to be superior too.