Mucking around on Beyond, I have to say, I'm pretty unimpressed with Beyond themselves as regards this book. There are a ton of problems, and they don't have any timeline to fix any of them, and indeed are posting rather elaborate (and yet poorly-explained) workarounds whilst carefully avoiding promising that they'll fix the issues. Some of the issues aren't even acknowledged. A few of the issues:
1) Centaur, Minotaur and Triton races aren't listed with the Theros lore. With other races which area-specific variants, you get a new version with the right lore. Here, they haven't bothered. If your players look at Centaur or Minotaur, they'll hear all about how they're from Ravnica and loads of information about guilds and so on. Literally the only way to get the right information right now is to go into Sources, and then into the Theros book, then find the right entry. This is pretty ridiculous and seems really lazy compared to what they did for previous books.
2) Supernatural Gifts, which are a mechanics-heavy effect, are totally and completely unimplemented. They haven't even tried. All they've done is say "Well, you can fake them by making a homebrew Feat and then putting in all the stuff to make them work". This is pretty insulting. It requires you to know how the elaborate and almost totally undocumented homebrew system works, and to go in and do it all yourself.
But what about how you CAN share homebrew stuff, Ruin? They went out of their way to PREVENT that here. So they didn't take any time to do this for us - which they could have - instead, they took time, actual time and effort to stop people sharing the homebrew replicas of the Supernatural Gifts. So every single person who wants to do this needs to INDIVIDUALLY know how to do it, and INDIVIDUALLY spend all that time and effort on it.
They could very easily have created all the Supernatural Gifts as Feats, and made them available to people who purchased Theros. But they didn't. Instead they did the opposite, and prevented players even helping each other with this. For me it's the going the extra mile to really make sure people can't help others with this that is the icing on the cake. Genuinely adding insult to injury there.
Awful.
3) Piety - doesn't function at all, and they've made no effort whatsoever to make it work or even be possible to track. An extremely major feature - arguably the core mechanic of Theros, and they just couldn't be bothered.
4) Artifacts of the Gods - equally non-functional, as they're connected to Piety, which they haven't bothered to track.
They have said they want to implement Supernatural Gifts eventually, though I feel like they're being more vague re: Piety, but it's a pretty unimpressive showing. They still haven't fixed the issues with Eberron marks, I note, either.
We're in the middle of a pandemic. Nothing is getting done right, or quickly, ANYWHERE. Might be worth keeping in mind.