Being the latest releases, Arceus: Legends, Brilliant Diamond, and Shining Pearl feature Pokémon with moves that don’t exist in the previous games, so their moves will be changed to equivalents based on the Pokémon’s level if they’re transferred to older games.
Pokémon Home will add support for Legends: Arceus, Brilliant Diamond, and Shining Pearl in the coming weeks with update 2.0.0.
When they transfer a Pokémon from Brilliant Diamond and Shining Pearl, they’ll receive Turtwig, Chimchar, and Piplup with Hidden Abilities.
Any Pokémon from one of the modern-day games will be switched into a Strange Ball when transferred to Legends: Arceus.