Exploring new 1.18 seeds I've found that oceans are HUGE, but rarely, if ever, have any islands in them. Generally oceans will have small islands, clusters of islands, and all kinds of stuff sprinkled around every couple hundred blocks. With the new oceans you can goes thousands of blocks without any land at all.

Furthermore I've found several small non-ocean biomes, that have 0-8 blocks above water. Potential showing that islands are having a hard time forming.

Seed -3396535 has about 3,000 blocks worth of ocean in a row, but hardly any land. If exploring this on a realm, or anything with less than 40 chunks of render distance, you can go ages without seeing any land at all.

*How to reproduce*
1. create world in 1.18.0.24 with seed: -3396535
2. teleport to -300 188 -1859
3. crank up the render distance to max (ideally 96 chunks+)
4. observe lack of islands

Images:
1&2 show larges parts of the ocean with no islands
3&4 show non-ocean biomes, that failed to generate any land