Welcome to the forum.

The thermostat is the first course of action. If it's stuck closed, the symptoms will be identical to those stated.

The other possibility is a decomposed water pump.........happens on occasion but it's relatively rare.

Please also state the ambient temperature when this issue occurs.

Also, please provide a history of the problem. Did it suddenly occur........or did it gradually occur.........starting at 90° and slowly creeping up toward 120°C. BTW, running the engine at close to 120° C. and then waiting for it to shut itself off is a recipe for a cracked head..........don't do it. If the temperature reaches 110°C. and you are not on a very long climb on a hot day........pull the vehicle to the side of the road and call a wrecker.