looks good and creative!
I think one chunk is a bit small, they could put a 2x2 chunks so people can have more space.
A "vote" system that people can vote if a building is: bad, good, awsome; and people with the most votes in the end of a certain time could get a reward(like a rank upgrade on java/special and exclusive cubelets, and for bedrock some exclusive cage/prefix/particle etc).
a survival i dont think would be THAT cool, but they can also try
The creative at a point will not be that popular, so what if they add as a SEASONAL EVENT??
then if it had exclusive itens, it would have even more people to participate!
if the mods get rid of NSFW builds and other innapropiate builds, i think this could be an AWESOME idea