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: Starting System
Description and operation Description The starting system includes the battery, starter, solenoid switch, ignition switch, inhibitor switch (A/T), clutch pedal switch (M/T), ignition lock switch, connection wires and the battery cable. When the ignition key is turned to the start position, current flows and energizes the starter motor's solenoid coil.Kia Stinger (CK) 2018-2023 Owner's Manual: Engine Mechanical System
Repair procedures Compression Pressure Inspection If the there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure. 1. Warm up and stop engine. Allow the engine to warm up to normal operating temperature.