Bad news, it looks like Apple Books isn’t going to connect to an iPad while virtualised. I did more testing, and it turns out the situation isn’t quite as grim as I’d feared, but it still isn’t good.
Then I had more bad news – a PCI card for hosting NVME SSDs I’d been eyeing has gone out of production. It’s problematic, because the alternatives really weren’t suitable.
I started looking around to see if there were any in the channel still, and found Amazon US had a few. So, I pulled the trigger, and then also on a pair of 4TB SSDs. So a thousand dollars gone, but hopefully this will let me consolidate a bunch of stuff onto my main machine, rather than having it on a Mac Mini fileserver.