I think the hidden treasure of area zero is really incredible, the story, the Pokémon option and the soundtrack, but SwSh's are good too, but Personally, I like the Pokémon Scarlet and Violet DLC the most, The Hidden treasure of Área Zero

SV's DLC. It has much more memorable characters, tons of Pokémon Black/White references, a great story, and is just more fun to explore.

SwSh's has Shiny hunting Legendaries but they're shiny locked in SV's DLC. Also, some of the Legendaries in SV's DLC can only be obtained by playing with other people.