Elytras / End ships no longer spawn?

I don't want to let Elytres spawn on my Minecraft Java 1.16 server. That's the reason that I want to make Elytres less often. But I don't want to disable the whole ending either. So there are 2 different methods. Don't let the ship spawn or the Elytra itself. Does anyone know how this works with commands / plugins? Or is there another method?

There are several plugins to prevent certain items from spawning here e.g. One

https://www.spigotmc.org/...U4I6JlTcYw