I can guarantee that anyone turning up and contributing or forking this project will not lead to the outcome of a improved piece of software.

It will lead to someone with the insight on how to make actual material improvements frustrated and angry that they don't have the technical skill (or time) to grapple with a complex codebase, and the people with the technical skill working on the codebase dismiss people with actual knowledge in different domains.

"Patches welcome" is not any kind of welcome. It's basically a euphemism for "fuck off, I don't want to have a conversation to make something better, I just want to hack on Feature X".