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: Wireless Power Charging (WPC) Unit
Components and positions Components Circuit diagram Circuit Diagram Repair procedures Removal • Handling wireless charging system parts by wet hands may cause electric shock. • Put on gloves to protect your hands.Kia Stinger (CK) 2018-2023 Owner's Manual: Rear Stabilizer Bar
Repair procedures Removal 1. Remove wheel nuts, wheel and tire (A) from hub. Tightening torque: 107.9 - 127.5 N·m (11.0 - 13.0 kgf·m, 79.6 - 94.0 lb·ft) Be careful not to damage the wheel bolts when removing the wheel and tire (A).