Contents:

The battery is in the trunk under the compartment cover.
When replacing the battery, disconnect the negative (-) cable (1) and remove the positive (+) battery fuse box (2).
Remove the battery mounting bracket (3).
WARNING - Touching metal surfaces in the trunk under the compartment cover

Do not touch metal surfaces in the trunk under the compartment cover while the engine is operating or hot. Doing so could result in serious personal injury. Turn the engine off and wait until it cools down or wear gloves to replace the battery from the luggage room.
Your vehicle has a maintenance-free, calcium-based battery.
When recharging the battery, observe the following precautions:
Reset items
Items should be reset after the battery has been discharged or the battery has been disconnected.
Kia Stinger (CK) 2018-2023 Owner's Manual: ISG (Idle Stop & Go) System
Components and components location Components Location 1. Battery sensor 2. Brake Booster Vacuum Pressure Sensor (BBVPS) 3. AGM battery 4. DC/DC Converter [200W] 5. DC/DC Converter [400W] 6. ISG OFF Switch 7. Alternator 8. Starter 9. Brake switch 10. Door switch 11. Seat belt switch 12.Kia Stinger (CK) 2018-2023 Owner's Manual: ESP Control Module
Components and components location Components 1. FR 2. RL 3. RR 4. FL 5. MC2 (SEC) 6. MC1 (PRI) 7. Damper 8. ESP control module connector 9. ESP control module bracket Repair procedures Removal [LHD] 1. Turn ignition switch OFF and disconnect the negative (-) battery cable.