Shapes Don't render above y-256. This is definetley true in the nether and it makes creating certain farms above 256 nearly impossible

Do you mean for custom world height? Is this 1.18? Is the world hight set with a Datapack? AFAIK world hight might be synced to client so maybe it’s feasible to be dynamic but I could be wrong, AFAIK masa is still refactoring the code for shapes it had some bugs but that might come after 1.12 rewrites, I am not speaking for masa ofc but iirc he said he would not work on tedious fixes too much till after the rewrites because the current code for 1.13+ will be kinda thrown out and the 1.12 code will be ported.