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: Master Cylinder
Components and components location Components 1. Master cylinder 2. Brake booster 3. Brake reservoir Repair procedures Removal [LHD] 1. Turn ignition switch OFF and disconnect the negative (-) battery cable. 2. Remove the brake fluid from the master cylinder reservoir with a syringe.Kia Stinger (CK) 2018-2023 Owner's Manual: Explanation of scheduled maintenance items
Engine oil and filter The engine oil and filter should be changed at the intervals specified in the maintenance schedule. If the vehicle is being driven in severe conditions, more frequent oil and filter changes are required. Drive belts Inspect all drive belts for evidence of cuts, cracks, excessive wear or oil saturation and replace if necessary.