It might be doable in markdown if the text is wrapped in parentheses like {{…}} if you calculate a md5 salted with the base name of the document you get an automatic ID close to a uuid. The downside is recalculation and updating the links that reference the block if content is added or changed outside of obsidian. Maybe reference the block with a unique id related to the document which can be an anchor text or number/timestamp like;
Document.md
{text goes in here
Multi line if needed}#20200619
Reference as;
[[Document#20200619]]
Transcluded as;
{{Document#20200619}}
It can get messy if it needs to be user editable outside of Obsidian, one needs to be aware that ids should be unique in a document.