I tried this with every release of the 1.20.1 version of the mod and the same thing happens with my current modpack. Every time I generate a new world and spawn in I am immediately launched high up into the air to the point the fall kills me. When I respawn it doesn't happen again, its just when I spawn in for the first time.

On top of that I spawn with 4 books that when using quark on its own I don't have. Book of Updraft, Book of Light, Nature's Wrath, and Book of Conveyance, which upon using them they just get readded to my inventory and nothing apparent happens. According to the tooltips they are some sort of spell books but I'm unsure why they are given to me in the modpack I'm using. I tried using Jade to identify the mod but it just lists them as Minecraft.

Using Quark and its dependancies on their own or removing Quark specifically from the modpack fixes both issues and from a glance at the config file it doesn't seem to be something I can fix on my own

Latest log:
https://gist.githubusercontent.com/XeeXeeVR/eee773e1f2e94c80bbc93f7ecafcd02e/raw/098f5dafff8e6290711729dd3fa623c110f52076/gistfile1.txt

I also have the modpack I'm using it with uploaded to curseforge so I'll link it too, release version 1.4 is the version with the issue: https://www.curseforge.com/minecraft/modpacks/fabricated-worlds-non-vr

Stellarity data pack tracks stuff via recipe unlocks, quarks automatic recipe unlock makes it give you effects & books, either remove stellarity or disable quark's automatic recipe unlock

Disabled it, did not fix the issue

Then your issue is another mod, try a binary search since quark doesn't give flight nor effects.