Ignore the 1-star reviews, the people who wrote them clearly did not install the plugin properly.
Use need to download the Kotlin library plugin that the author provides in order to use this plugin.
The plugin works incredibly smoothly and without any lag or errors on PaperMC 1.16.5. It's not tested on other forks of Spigot I think, so if it doesn't work on x version, then it's incompatible and you should report it in discussions, not in the reviews section.
The author has been incredibly responsive and if you're leaving 1-star reviews, then you have not been communicating or trying to talk to them and lying through your teeth.
https://imgur.com/a/OhAkqZF
Here's what it looks like when you install the plugin correctly and you're using a compatible version of Spigot or Spigot fork.
https://pastebin.com/f8mH38z9
Here is my config.yml to remove any "x1" "x64" stack holograms to achieve just having the 3D items without nametags.
Hope this helps, and please talk to the author about errors or incompatibilities in the Discussion tab instead of using the reviews to do so. That's just bad ettiquette and rude.