That is what is technically called a bummer, as I was investigating its possible use (I am not an Adobe lover). But it reminds me that as far as support is concerned, we are perhaps over-assisted here! (Can anyone point to another major software product with such rapid problem-solving facilities?)
Thanks to all those, both paid and unpaid, who provide generous Dorico support! 
David
I’ve got the 3 Affinity products and use Designer all the time, Publisher occasionally and haven’t used Photo for a while. All do what I want (my needs are relatively few), but I’ve found that Publisher is nowhere near stable as Designer.
I’ve only needed to contact Serif once and was answered within a few days. IIRC I used email rather the forum.
Any comments regarding v2 Affinity Publisher would be appreciated. I wouldn’t say I have large projects, but if it has improved I can consider using it.
For larger projects I think you have two options that have a fairly easy GUI: Adobe InDesign and Adobe FrameMaker. Both are somewhat expensive, but do the task without any problems. InDesign also have a book feature like FrameMaker but is probably less capable if you need advanced features like autogenerated lists, index, glossary etc. In FrameMaker I have done a book with ca. 550 music samples and another book with ca. 6,000 images, both using dynamic linked graphics. No problems. FrameMaker only runs on Windows.
Daniel S. wrote a manual for a “famous software” in FrameMaker. Current Dorico manual seems to be a merged conversion from individual XML pages, but I can be wrong.
There is always various free TeX versions. Far superior software, but can be experienced as a bit “difficult”.