Pretty much what was said above by ooshima. However I will say Ramuh is 99% about coordination. I don't think people will have an easy time winning in pugs without some form of voice communication. Fighting him feels like a mix if t6\8 with a twist, I did beat him even got tank shield. However if people die you can recover. You can even use healer, tank, or melee lb. The fight has some small rng elements like who thunderstorms are going to be on and the random ones on the field. Melee need to be good at moving in and out. All in all don't look forward to following a cookie cutter strat found on a video. Learn the fight develop your own conventions because otherwise it will be a pain.