This is an official PlotSquared addon which hides your plot.
The download is available at Modrinth.
This addon requires PlotSquared and ProtocolLib to be installed. You can get them below:
You can set the hide flag on a per-plot or global basis.
Invisible plots can be bypassed with the permission plots.plothider.bypass.
Support is available on discord server. If you encounter an issue or want to add a feature, you are welcome to open an issue or raise a pull request.