If you are a collector preserving your digital library, or a homebrew enthusiast testing the limits of the Switch's hardware, the 2021 versions of these games represent the definitive way to play.
Published: 2021 (Retrospective & Technical Deep-Dive)
However, for the average fan in 2024 and beyond: The best way to experience the 100+ hours of content in Age of Calamity or the 200+ hours in Definitive Edition is to purchase them legally. The NSP files are out there, but the peace of mind of a clean, online-enabled save file is worth the price of admission.