PTU - Single Biggest Hit

Trainer is:
1) Electric Ace - for Move Sync (Electric)
2) Cool Expert - for Style Entrainment (Cool)
3) Chef - for Dietician + access to Spicy Wrap
4) Duelist - for Type Methodology + Duelist's Manual

Pokemon is:
1) Alolan Geodude @ level 100
2) Adamant Nature (or any other +Atk)
3) Has Underdog's Strength + Realized Potential
4) Has 7 Protein (from Dietician)
5) Has used Move Sync on Explosion for Electric Type
6) Is holding an Electric Type Gem
7) Has a Spicy Wrap Food Buff
8) Is on Electric Terrain
9) Has +6 Attack Combat Stages and is going to Crit

    BS  US  RP Vt Lvl   Ttl   CS
HP   4  +1             =   5
Atk 10  +1 +15 +7 +110 = 143 x2.2 = 314 total Attack after all modifiers
Def 10  +1             =  11
SpA  1  +1             =   2
SpD  3  +1             =   4
Spe  2  +1             =   3

Electric Sync Explosion (DB27)
+ Gem (DB28) -> 8d12+80
+ Charge     -> 16d12+160
+ Crit       -> 24d12+240
+ 6CS Attack -> +314
+ Sniper     -> +3d10
+ Spicy Wrap -> +10
+ EleTerrain -> +10
             =  892 damage on Neutral
+ Exploit    -> +5
+ Duel Mnl   -> +5
+ Effective  -> 1353 damage on SE
+ Dbl Effect -> 1804 damage on DSE

Turn 1 -> Trainer uses Style Entrainment to grant Sniper, Geodude uses Charge
Turn 2 -> Trainer uses Duelist's Manual to double bonus from Exploit, Geodude uses (Electric) Explosion while trading in Type Gem and Spicy Wrap buff. This attack is a Critical Hit made on Electric Terrain.