So I know that the title is pretty vague and I could search for the solution but I did, and literally, I didn't see any post with a title resembling my issue. Currently I have Multiplayer and Harmony+ Hugslib installed, but even on plain vanilla, back when I bought Ideology, I started getting https://gist.github.com/b28a37d92407cd339fa32367d2559842 (https://gist.github.com/b28a37d92407cd339fa32367d2559842) those errors thrown whenever launching the game without mods. I have found NO solution and no other problems similar to mine.
Do I have to plain reinstall and hope it fixes it? Will I lost my modlist?
Reinstall won't fix it, since uninstal don't delete surplus files.
Manual delete the installation folder, or when you want keep the mods, just the Data folder.
Then reinstal/repair it.
Oh my god, that fixed it! Thank you so much!