Use NXDumpTool; it allows you to choose which files to dump for any game in your console.I know that but I’m asking about the itemparam file.
BTW, that file is in the Bcsv folder. Yeah, I have extracted it myself (as well as the whole content of the BCSV and Stage folders) But for obvious reasons I can't share them (better to learn how to extract it yourself anyway).
Also, I couldn't find where in that file the durability might be stored.