Galarian Zapdos's best moveset in Pokémon GO is Counter and Brave Bird, with 17.81 damage per second, and it can deal 559.8 damage before Galarian Zapdos faints. This is true when battling in neutral weather.
All Galarian Zapdos movesets ranked
Here is a complete list of Galarian Zapdos movesets in Pokémon GO, ranked by their DPS and TDO. You can change the weather and the opposing Pokémon.