Galarian Shadow Zapdos's best moveset in Pokémon GO is Counter and Brave Bird, with 21.17 damage per second, and it can deal 554.4 damage before Galarian Shadow Zapdos faints. This is true when battling in neutral weather.
All Galarian Shadow Zapdos movesets ranked
Here is a complete list of Galarian Shadow Zapdos movesets in Pokémon GO, ranked by their DPS and TDO. You can change the weather and the opposing Pokémon.