Data Pack validation failed

Hey there,

I know this topic is not really new but I still wasn't able to fix that problem.
after a longer break I started to work on my mod again. So I jumped from 2020.2 to 2022.2 before with no problems. But after trying to change to the version 2023.1 I wasn't able to create a new world due to the failed validation of data packs.

I've already looked up other related topics but none of the solutions fixed my problem. It fixed only a few parts of it. 
These were the solutions I tried:

• rebuilt the gradle multiple times
• Deleting custom fluids in the old version and then recreating them in the newer version (fixed other errors)
• Reimported the workspace, also from the old functioning version
• deleted problematic biomes that caused worldgen error (only visible for me in the console of 2022.2). There was no specific _modifier.json for the biomes that I was able to delete
• recreated (an deleted some of them) every block or structure that is being generated in my mod
• looked through every mod element to see if there are missing dependencies or mod elements (maybe I missed something there)
• also tried MCreator Version 2022.3

After all of this testing there are no visible errors in the console that I can fix with my knowledge. It still says "Data Pack validation failed!".
The only thing that works is to do my mod again in a new workspace.

My guess is that this is releated to the fact that the generation of the world got changed dramatically within vanilla Minecraft 1.17 (e.g. new cave system).
Is there anything left I can do or try?
Or is it a general problem when switching the versions like that?

That's my current Console Output in 2023.1:
https://pastebin.com/CFxRFugW

(if workspace is needed. I can send it via private chat or smth.)