This is really the first time I've managed clear Palmer in the 49th battle, but that's also due to me knowing about competitive pokemon.
The team consisted of the following:
Garchomp: Jolly nature Focus Sash
4 HP/252 Atk/252 Spe
Outrage
Swords Dance
Fire Fang
Earthquake
Salamence: Adamant nature Lum Berry
4 HP/252 Atk/252 Spe
Outrage
Dragon Dance
Fire Blast
Earthquake
Lucario: Adamant nature Life Orb
4 HP/252 Atk/252 Spe
Extreme Speed
Close Combat
Swords Dance
Crunch
This trio focuses purely on sweeping through raw power alone. Garchomp being the main lead that can 1-2 hit KO most pokemons, with Lucario acting as an answer to ice-types and clean up duty with Extreme Speed while Salamence acts as a back-up sweeper. If given any chances to boost, they all can sweep on their own and Salamence post-dragon dance becomes the fastest mon on the field without a rare choice scarf user or priority.
This can 100% translate to the other 3 modes with how consistent they can brute force through everything. Feel free to copy.