Koei Tecmo has said numerous times that Atelier Ryza: Ever Darkness & the Secret Hideout has been their most successful entry in the Atelier series. That would make a sequel quite likely, and it appears the company is already hard at work on one.
An Aussie rating for Atelier Ryza 2: Lost Legends & the Secret Fairy has popped up, and as usual, the listing says the release will be multiplatform. It's definitely likely the sequel will find its way to Switch, and we should hear some details soon. With Atelier Ryza: Ever Darkness & the Secret Hideout releasing back in 2019, it's pretty surprising to see a follow-up already being rated!