Hey. Update ZenUV button is needed to avoid an error when deactivating the library. That is, the process takes place in two stages, first we unregister ZenUV Core library and then we run the standard procedure for updating the blender addon. However, we cannot influence how Blender does it. Obviously, in your case, the only way to update is manually.
https://zenmastersteam.github.io/Zen-UV/latest/installation/#manual-update