Does what it says. The bad reviews are probably from people who don’t know how to use it. I would recommend it! Overall, a great developer and a helpful community contributing on GitHub. It also adds really nice eye-catching visuals to vanilla items.
The second plugin I've bought from this dev that just doesn't work. 1.20.4 with console errors and no functionality. No faith it will be fixed as ItemsAdder seems to be the only mod the dev gives any attention to, the rest are soon forgotten about despite being paid plugins.