What will be announced has not finally been decided yet. But certainly US, Korea will be announced (sic). And then that model might be available as a second (wave) launch.

The corners on the S25 Ultra are a bit more rounded, the edges are flatter, and the bezels seem to be slightly thinner. The S25 and S25+ models have the same screen size as the S24 models, at 6.2 and 6.