CubicChunks in Spigot 1.16.5?

Hello.

I am making a sort of France-like server on Aternos with my friends, with the fact we will build the Eiffel Tower, is it possible to have the height limit be above 256 with Cubic Chunks? I am unable to find the plugins in the list, while it told me the plugin is apparently there.

Best regards.

Quote from Roman

Those are mods. Spigot is made for plugins

Is there any way I could increase the height limit in that case while keeping the cross-play between bedrock and Java?