I spent ages building some of my ship, until i realised there was a 256 height limit is there anyway I can buy more? If not I may have to quit because it would take to long to remove or redesign.
Can't build higher then 256 hight level. The server has no control over this as it is a Mojang built in limit. You could ask Leeeroieee if he would be kind enough to help move your build for you.
Use schematica mod (google it) to save your design so you don’t lose it and start again. No point quitting for something fixable, even if it take a little bit of work. Rebuilding and building many times is part of Minecraft.
I was using the litematica mod and was building it from that, it's just that it isn't a small build and to move it down a through using /jump and hard work is not even worth it. See image below lol.