a Team for Leon in SwSh, but designed in a similar way to BDSP Cynthia

The Champion Fight (please note that I included the Starters and the Pokemon that accompany them in the same team)

Aegislash @ Leftovers  
Ability: Stance Change  
Level: 62  
EVs: 252 HP / 252 Atk / 4 SpD  
Brave Nature  
- Shadow Sneak  
- King's Shield  
- Shadow Ball  
- Sacred Sword  

Dragapult @ Dragon Fang  
Ability: Clear Body  
Level: 62  
EVs: 4 Atk / 252 SpA / 252 Spe  
Hasty Nature  
- Dragon Darts  
- Shadow Ball  
- Thunderbolt  
- Fire Blast  

Haxorus @ Life Orb  
Ability: Mold Breaker  
Level: 63  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Dragon Dance  
- Dragon Claw  
- Earthquake  
- Poison Jab  

Seismitoad @ Rindo Berry  
Ability: Water Absorb  
Level: 64  
EVs: 4 HP / 252 SpA / 252 Spe  
Modest Nature  
IVs: 0 Atk  
- Earth Power  
- Hydro Pump  
- Sludge Wave  
- Focus Blast  

Mr. Rime @ Heavy-Duty Boots  
Ability: Screen Cleaner  
Level: 64  
EVs: 12 HP / 248 SpA / 248 Spe  
Timid Nature  
IVs: 0 Atk  
- Ice Beam  
- Thunderbolt  
- Psychic  
- Nasty Plot  

Rhyperior @ Leftovers  
Ability: Solid Rock  
Level: 64  
EVs: 252 HP / 252 Atk  
Adamant Nature  
- Earthquake  
- Stone Edge  
- Megahorn  
- Swords Dance  

Cinderace  
Ability: Libero  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Pyro Ball  
- Sucker Punch  
- High Jump Kick  
- Acrobatics  

Inteleon @ Scope Lens  
Ability: Sniper  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Focus Energy  
- Snipe Shot  
- Ice Beam  
- Dark Pulse  

Rillaboom @ Assault Vest  
Ability: Grassy Surge  
Level: 64  
EVs: 252 Atk / 4 Def / 252 Spe  
Adamant Nature  
- U-turn  
- Wood Hammer  
- Drain Punch  
- High Horsepower  

Charizard-Gmax @ Charti Berry  
Ability: Solar Power
Level: 65  
Gigantamax: Yes  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Fire Blast  
- Air Slash  
- Solar Beam  
- Scorching Sands  

Now for the rematch

The weather for the rematch is always permanent sun meaning that unfortunately Siesmitoad and Inteleon are not going to be used in the Rematch since they will be replaced by Rhyperior and Cinderace 

Aegislash @ Choice Band  
Ability: Stance Change  
Level: 80  
EVs: 248 HP / 252 Atk / 8 SpD  
Adamant Nature  
- Close Combat  
- Shadow Sneak  
- Shadow Claw  
- Iron Head  

Dragapult @ White Herb  
Ability: Clear Body  
Level: 78  
EVs: 252 SpA / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Draco Meteor  
- Shadow Ball  
- Thunderbolt  
- Fire Blast  

Haxorus @ Life Orb  
Ability: Mold Breaker  
Level: 78  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Swords Dance  
- Scale Shot  
- Close Combat  
- Poison Jab  

Mr. Rime @ Light Clay  
Ability: Screen Cleaner  
Level: 79  
EVs: 252 HP / 4 SpA / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Ice Beam  
- Thunderbolt  
- Light Screen  
- Reflect  

Rhyperior @ Rindo Berry  
Ability: Solid Rock  
Level: 79  
EVs: 244 HP / 252 Atk / 12 SpD  
Adamant Nature  
- Earthquake  
- Stone Edge  
- Heat Crash  
- Swords Dance  

Cinderace  
Ability: Libero  
Level: 79  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Pyro Ball  
- Sucker Punch  
- High Jump Kick  
- Acrobatics  

Rillaboom @ Assault Vest  
Ability: Grassy Surge  
Level: 79  
EVs: 252 Atk / 4 Def / 252 Spe  
Adamant Nature  
- U-turn  
- Wood Hammer  
- Drain Punch  
- High Horsepower  

Charizard-Gmax @ Charti Berry  
Ability: Solar Power  
Level: 80  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Fire Blast  
- Air Slash  
- Solar Beam  
- Scorching Sands