The "Eternal Collection" is the definitive edition, bundling the complete Diablo III experience:
To install, ensure your Switch runs the latest firmware and use a trusted installer like DBI or Tinfoil. Note that while rare, some Russian-language pages note a script-breaking bug on Act III involving arcane ballistae—it’s advisable to keep a pre-Act III save backup when installing custom content. Diablo III Eternal Collection -NSP--Update 2.7....
: Includes the Reaper of Souls expansion (introducing the Crusader class and Adventure Mode) and the Rise of the Necromancer character pack. The "Eternal Collection" is the definitive edition, bundling