1. First you need to locate the patch files, which will all be downloaded into this folder usually

   C:\Users\(You)\AppData\LocalLow\Unity\com_proximabeta_NIKKE\naps

2. To only get the new files I use the search function on the explorer by typing "date:patch date" and it will only list the new files. Then you copy them all over into a different folder.
3. You need a tool called NAU to decrypt the encrypted files, you can download it here

   https://nikke-modding-wiki.vercel.app/downloads/NAU.rar

4. And you also need the latest keys. There's two ways to get them. Either go to this site

   https://nikke-modding-wiki.vercel.app/modCreation

   and CTRL+F NAU Key and you'll find the option to drop your settings.json file there. Where you can find that file is written on there. Or alternatively you can download the generator.js script and run it yourself with VS Code, which you need to install first then. Latest keys right now are v27.
5. After making sure you have the latest keys you can open cmd and run a command line to decrypt the files in the folder you copied over earlier. It should look something like this

   NikkeAssetUnpacker.exe d -i "input folder" -o "output folder"

   If something isn't working consult the readme that came with NAU, you might need to download .NET Runtime 8.0.
   It should only decrypt the files that actually had encryptions this way, but some files aren't encrypted and those will just be skipped.
6. Then you need a tool called AssetStudio. I use this version, there's also some other forks. You don't have to install it, just unpack.

   https://github.com/zhangjiequan/AssetStudio

7. Open AssetStudio and then select File in the top bar and Load folder and select the folder with the decrypted files and it will load them all in. And then you can view them on the Asset List and right-click to export the files.
8. Some files are still in the other original folder since they weren't encrypted, but it's mostly not the interesting stuff. You could simply merge the decrypted folder with the first one and overwrite the encrypted files there, but personally I wouldn't because AssetStudio takes quite a while to load all the files and the more there are the longer it takes.

And that's it. If you check the mod site above there's some explanations there and some other methods to do stuff so that might be easier, I dunno really.