So ive been trying for like 2 days totalling up to about 60 attempts and i cannot beat Radomus. (Shelly took longer though) But during Shelly's battle i would always go to the last 2 pokemon and loose there but with Radomus the first 2 or 3 pokemon would sweep my full lvl 60 team.
Sharpedo lvl:60 Crunch, Skull Bash, Aqua Jet, Destiny Bond. Item: Power Bracer (To slow it down due to Trick Room)
Warein lvl:60 Stockpile, Blizzard, Brine, Aura Beam. Item: Wide Lens (To increase Blizzard accuracy)
Decidueye lvl:60 Synthesis, Leaf Blade, Spirit Shackle, Brave Bird. Item: Soothe Bell (IDK why it has a Soothe Bell)
Ampharos lvl:60 Discharge, Light Screen, Power Gem, Cotten Guard. Item: Light Clay (For Light Screen which many guides say is useful but doesnt really help)
Macargo lvl:60 Flamethrower, Shell Smash, Strength, Earth Power. Item: Protective Pads (IDK why)
KlingKlang lvl:60 GearGrind, Shift Gear, Discharge, Rock Smash. Item: Pure Incense (IDK why)
I also have infinite Super Potions and Revives (Cotton Candy) at my disposal and i have many Heart Scales for the move relearner as well. Many other guides do not help that much as well and the light screen seems innaffective. For many other gym leaders i have stratagies but for this one i get sweeped too fast and therefore have no time to experiment. Im willing to grind to beat this as well.