Two teams have actually published what a floating city looks like: OCEANIX Busan, built with BIG, SAMOO and UN-Habitat, and the Seasteading Institute's Floating City Project in French Polynesia. Both landed on the same module — a hexagonal platform, assembled on shore and towed out to a mooring.
The renderings are quieter than you would expect. Grey-teal Pacific water, timber decking, rattan screens, biorock accreting on the hulls. This system takes that restraint literally: an unlit night-sea ground, one warm value for everything people touch, and chart-annotation rules doing the structural work.