DLC for recent (comparatively) 3D Sonic games has been very muted, so my expectations are a little low. Sonic Lost World had a few free Nintendo crossover lands, and Sonic Forces hosted "Episode Shadow" and "Super Sonic" side stories. But as far as major expansions go, things are light. Maybe Sonic Frontiers will change that, and given the nature of the mysterious Frontiers universe itself, it would be an easy candidate for whisking players away to far-off lands. The Cyber Space aesthetic is already kind of doing that.