I have a custom modpack required for use for my server and a server member told me that the sword weapons have the same durability.

They did some testing and told me that they were all the same, so I tested to see if my modpack was an issue but it was the same just with MCDW only. As for the other weapon types, I have not tested them and assumed they are the same.

The image below is an image of the Obsidian Claymore with only max 250 durability.