Do I need to beat the main game to encounter Darkrai in PL:A?

Question

I was scrolling through the Pokémon news section of the site and saw this:

Darkrai can also be encountered in PLA. If you have play records from Brilliant Diamond or Shining Pearl you'll gain access to a special research request for Darkrai.

What requirements with BDSP do I need to get Darkrai as it is not mentioned?

Answer 1

If the save file is present, players will be able to take on a research request in Pokemon Legends: Arceus once the credits roll.

Source

Yes gamerant got something right