Maybe this does already exist and I have just not been able to find it - is there a way to replicate the contents of a region in one layout to a region in another layout? Say for example I had a header region in a layout, with a logo block and a menu where I have made a bunch of configuration adjustments for visibility and classes and whatnot. I then have 5 other layouts where I want the header region blocks to be replicated exactly as in the first. And then if a change is made to one of these blocks, it then applies across all of the layouts. I suppose I am thinking of a layout (in a header region for example) that is embeddable across several layouts
Are there any contributed modules that are attempting to achieve functionality somewhere along these lines? Or any in development?
I think that the Copy Blocks module should do exactly what you want.
https://backdropcms.org/project/copy_blocks