I've gone through the Peritext paper several times, and attempted to implement support for lists/tables/sections myself, but found it to be difficult owing to the limited scope of the original paper. I reached out to Martin Kleppman about this, and this is what he told me:
"Thanks for your message. I've written up a document on how to extend Patreon with nested block elements such as bullet points. It's not properly published yet, but you can find a draft here: https://martinkl.notion.site/Block-elements-in-rich-text-CRD...
My colleagues are currently in the process of integrating this algorithm into Automerge, and creating bindings to the ProseMirror rich text editor."
Personally, I found the document to be very helpful.
I've recently implemented a rich text editor on top of Automerge and Peritext that supports blocks, inline-blocks (or whatever you call them: images, tables, etc.), unaware that this was in the works. The implementation ended up _very_ close to what's described in the linked post.
"Thanks for your message. I've written up a document on how to extend Patreon with nested block elements such as bullet points. It's not properly published yet, but you can find a draft here: https://martinkl.notion.site/Block-elements-in-rich-text-CRD... My colleagues are currently in the process of integrating this algorithm into Automerge, and creating bindings to the ProseMirror rich text editor."
Personally, I found the document to be very helpful.