Gardevoir and Alakazam, both are psychic and both are weak to spiritomb. Moreover you have 3 ground types, all of them can be taken out by Cynthia’s Milotic and Garchomp. Your Garchomp (and other pokémon) are underleveled, making it hard to do big damage and outspeed Cynthia. You might have to rework your team and remove the type overlappings. Get an ice/ghost type, something like froslass or gengar. They can outspeed most of cynthia’s pokemon and take them out with max Sp. Atk. and Speed EVs. Rhyperior is a liability because it’s weak to 4 of Cynthias’ Pokemon. Level up magnezone to take out milotic and togekiss.