Youtube vdeos are nice to get started, and hunting the web for extra info can be fun when I have some time to waste on it, but I still prefer books as a way to absorb in-depth knowledge. Are there any recent books out there on XCP/NG, Xenserver or Xen Orchestra?
I am not aware of any recent books on the topic and but they do have their documentation page which is constantly being expanded. https://xcp-ng.org/docs/
I did this video to be a complete start to finish guide for XCP-NG https://youtu.be/q-jKs62b6Co and I have a few others on the sub topics. I have been asked a few times about books, but I am not sure there is enough demand to write one.