Remember, these are my opinions, and I bear no ill-will towards the author or their work. Also, unless I fully convince you - the author - or others have the same critiques, I wouldn't recommend changing anything about your story.
First, I want to say I loved your descriptions. You got across what was going on and helped paint a picture in my head. However, sometimes I noticed you added an unnecessary adjective. The sentence "The mantras felt clogged up in my throat that weakly coughed out terrifying cries." can be shortened to "The mantras felt clogged in my throat, coughing out terrifying cries." and still make sense. And if you want to assert dominance - ie they just feel clogged, they were clogged - you can remove the word felt altogether: "The mantras clogged up in my throat, coughing out terrifying cries."
The other thing I noticed was your opening chapter alienates your audience by not cluing in the reader on why what's happening is happening. In other words, the reader only knows one thing: stuff is happening. One way to reverse this effect is to make the protagonist confused as well. This gives the reader consolation that they aren't the only ones not understanding anything. If you have access to YouTube, I recommend checking out The Closer Look's video on the movie Tenet, "Tenet - The Best Kind of Failure". They go into more detail there and are just an all-around great place for creators to hone their craft.
Overall, your story was amazing, and I can tell it's going somewhere. I hope this helps you become a better writer and that you have a great day! :)
