I read the Paste Special, find to very fascinating, have a rough idea for implementing it. See, i am new to this project and haven't created any PR for this project, so I might not be a participant for this, sharing my idea so that I can contribute to OSS anyhow.
I guess, HTML part is working fine with this plugin : joplin/packages/turndown-plugin-gfm at dev · laurent22/joplin (github.com)
we have to work on the CSV, PDF.
I think it would be easier to discuss it if we can make an issue in the main Repo. of Joplin. also, it is easier to implement this with some tweaks.
which I had already shared 15 days ago here
we can also modify this core package to enhance as per our requirements, would love to know your feedbacks