Just to chime in that this particular version isn't working for me either. In an effort to be more than just a "me too!", I dug around in the files a bit. I'm certainly not a lua or wow addon expert, so forgive me if I wind up being wrong.
Alliance.lua and Horde.lua do indeed exist in the Dragonflight guides, and they are referenced in GuideList.xml (which I believe is for WOTLK) and GuideList-classic.xml (for Classic). They don't seem to be referenced at all in GuideList-mainline.xml which I believe is what is used for Dragonflight.
Merely adding them to GuideList-mainline.xml doesn't resolve the issue and I don't have a working older version to determine what other issues there may be. I assume Alliance.lua/Horde.lua have vastly different contents, groupnames, etc. for the mainline version.
Again, I could very well be wrong about all of this. If I am, at the very least I'm another person who is having issues with the latest Dragonflight version of RXP and that's with deleting the old files, saved variables, and extracting everything using the latest 7-Zip.
Regardless of what the issue may be, thank you for getting everyone these releases!
Edit: For the sake of being complete, I'll add that I tried installing the free version from github and copying just the guides folder over and that still didn't work. That's what lead me to digging around in the guide files in the first place.