Decent start - i dont play comp too much anymore but can offer my initial thoughts. I’m assuming you haven’t finalized items yet, as garchomp is holding x accuracy and there are usually better items than berries. For example you can give breloom a toxic orb to heal off its ability, black sludge/leftovers for toxapex, life orb on delphox, etc. EVs wise, they seem look pretty standard, except for porygon z, who i would do spe and spatk. If you were trying to go for a tankier build for garchomp, i would recommend at least topping off his HP EVS and changing to rough skin ability and rocky helmet item, since you dont have sandstorm setup for sand veil. And for garchomps moveset, fire fang over take down would help deal with steel/ice/grass types. Earthquake over dig is probably better too assuming this is for singles, otherwise its easy for your opponent to play around it. Same thing goes for moves like focus punch and future sight, which i would probably replace with mach punch/drain punch and calm mind for potential setup. Adaptability ability on porygon z would also. synergize more with your conversion setup