The new arc: Wonder Voyage
Main characters:
Liko
Roy
Dot
Ult
A new Pokégirl with a Ditto (clearly to promote Pokopia)
The key visual also features:
Koraidon and Miraidon
All the Scarlet & Violet legendaries
Ogerpon
It also looks like they’ll be adapting multiple games into the anime, including:
Pokémon Unite
Legends Z-A
Pokémon Pokopia
Pokémon Sleep
For the new main villain : well, he's an Angel 2.0, a giant eye tentacles
by Fancy-Wolverine-4233