Minecraft plugin (plot border)?

I have a problem and I have an MC server with plots and would like to add the plugin margins https://www.spigotmc.org/...-12.72903/ it also works but I only have blocks that float above the plot can someone recommend another or another way?

I don't see what's wrong in the picture. Looks like it will work fine.

Would like to have it below the earth

When you create the plot world, just set the plot margin height to one block lower than the path and the rest