Use a standard installer to side-load the 1.3.0 NSP. This will "patch" your base game without deleting your save data.
The update, released on March 7, 2023, primarily added compatibility for Wave 3 of the Expansion Pass and introduced new features to the Somniel. Key Features & Changes in Update 1.3.0 Expansion Pass Wave 3: Adds two new DLC Emblem Bracelets: Chrom/Robin (Emblem of Bonds) and (Emblem of Heroes). Fire Emblem Engage Switch XCI NSP Update 1.3....
: If you're using a game version obtained through unconventional means, ensure that updates are compatible and obtained safely. Use a standard installer to side-load the 1
A: Yes. The update is cumulative, so it includes all previous patch data. released on March 7