Rhyperior
Alo guys yesterday I will fighting one heatran with one friend he use rhydon more less for me around 2.5 CP and I rhyperior with 15 atk max lvl at 3500 CP and him pass me at DMG lolen how hapent this I watch rhydon hit very faster from rhyperior
Answers
Well... The only other reason I can think of is team composition. Did you only have the Rhyperior and no other optimal counters? Rhyperior is absolutely better than Rhydon, but if he had other optimal counters to Alolan Raichu, then he would indeed do more damage.
If your friend used any pokemon from the link below then they would absolutely do more damage than you. It's likely that your Rhyperior did more damage than his Rhydon, but his other pokemon outperformed your other team members.
https://www.pokebattler.com/raids/defenders/RAICHU_ALOLA_FORM/levels/RAID_LEVEL_3/attackers/levels/35/strategies/CINEMATIC_ATTACK_WHEN_POSSIBLE/DEFENSE_RANDOM_MC?sort=ESTIMATOR&weatherCondition=NO_WEATHER&dodgeStrategy=DODGE_REACTION_TIME&aggregation=AVERAGE&randomAssistants=-1&friendLevel=FRIENDSHIP_LEVEL_4
