I had the same problem a few months back. It's unlikely you have exactly the same issue as I did, but mine was in 'x64f.rpf'. In 'v_signs.rpf' I believe .
As a quick eliminatory test, backup your 'mods' folder 'x64f.rpf' (or game folder one if there's not one in your 'mods' folder) & then revert it to vanilla & see if the crash still occurs.
If that doesn't fix it, revert it using the backup you made & continue below.
How to diagnose the issue:
- The way to diagnose this is to start by creating a folder next to your 'mods' folder called something like 'mods - REMOVED'.
- You then move '.rpf' archives & folder structures one by one from your 'mods' folder to your newly created 'mods - REMOVED' folder (move them/drag & drop, it's quicker, no need to copy & paste & they won't use up any more space)
- Test load the game inbetween each change until the game loads & you get past the crash & find the archive/folder structure that is causing the issue
If it's in a folder structure, like the 'update' one that leads to 'dlcpacks' for example, use the same process of elimination to diagnose which '.rpf' archive within that folder structure causes the issue. Just leave the update\x64\dlcpacks etc folder structure in place, create the same folder structure in 'mods - REMOVED' & move dlc folders one by one from the 'mods' dlcpacks folder to the 'mods - REMOVED' one.
...\mods\update\x64\dlcpacks\ <!-- move dlc folders from here -->
...\mods - REMOVED\update\x64\dlcpacks\ <!-- to here -->
You can work the other way too, by placing files/folders back into a newly created empty 'mods' folder until you find the crash, but given that you crash on startup, it's quickest to remove one by one from your 'mods' folder to another folder, as then you don't waste any time waiting for the game to fully load, you just load until you get the crash, exit out & then try the next one etc.
Once you figure out what '.rpf' the issue exists within, use the same process in OpenIV to revert files/folder structures within that archive back to vanilla until you figure out exactly which file caused it.
That's the cleanest way of doing it. It'll be tempting to just skip that last part once you can load your game, but it may not be advisable. Ideally, you don't want to leave a mix of mismatched files in your game that could possibly cause a new issue in future.
If however, you know exactly what has been installed to that archive, or you know nothing modded exists within it, it is possible to skip that part, just be sure you know exactly what you are doing.