Is there any way to have a separate instance of Gutenberg created as a custom field?
Just like we can pick WYSIWYG Editor as a field type, it would be an actual Gutenberg instance where blocks can be used as they would on the main content area.
I don't have an answer for you, but that's an interesting idea. If so, I'm guessing it would have to be the Isolated Editor rather than the full Block Editor. But I like the idea and I hope it's possible!
@peter what I meant is an actual Block Editor instance as a custom field.
Right now, the Block editor is only allowed on the main post content area which is very limiting.
This prevents relevant portions of a page that outputs the custom field's content limited at best to text and images and videos using the WYSIWYG editor as a field type, or high maintenance using the Custom HTML field type.
Let's say that I want to use a fancy price table with before and after comparison element separated from the main content. That would translate to a group of fields + building the markup/CSS/JS, manually maintain and customize it over time.
If there was a Block editor instance, I can just drag and drop the relevant block elements from some blocks plugins, and change their content.