Koraidon (Apex)'s best moveset in Pokémon GO is Splash and Struggle, with 12.89 damage per second, and it can deal 468.3 damage before Koraidon (Apex) faints. This is true when battling in neutral weather.
All Koraidon (Apex) movesets ranked
Here is a complete list of Koraidon (Apex) movesets in Pokémon GO, ranked by their DPS and TDO. You can change the weather and the opposing Pokémon.