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: CVVT Oil Control Valve (OCV) [Bank1/Exhaust]
Specifications Specification Item Specification Coil Resistance (Ω) 6.9 - 7.9 [20°C(68°F)] Description and operation Description Continuous Variable Valve Timing (CVVT) system advances or retards the valve timing of the exhaust valve in accordance with the ECM control signal which is calculated by the engine speed and load.Repair procedures Removal 1. Disconnect the negative (-) battery terminal. 2. Remove the tailgate back panel. (Refer to Body - "Tailgate Back Panel") 3. Disconnect the license lamp connectors (A). 4. Remove the license lamp (A) after pressing the locking pin.