Blocks field: Expand/Collapse all blocks

When working on a page with many blocks in a blocks field, and using preview: fields, I find myself wishing there was a way to expand all block previews so that all content is visible, helping me find the particular piece of content I wish to edit.

Equally, I’d find it helpful if there was a “Collapse all” option so that I could quickly get back to the single list of blocks present on the page, instead of having to click on each open block to “close” it.