How can you train for anything then? How do people play for any sports when training is not for real?

You need to learn how to handle your equipment, cooperate with others, and what tactics you should use. You need to learn that before real combat because if you do not know how to do it when you are not afraid you will for certain not know that when you are afraid.

If you do something it is second nature to you then you have a better chance to do it if you are afraid because you do not need to think about that. If you have learned to drive a car compared to how it was the first time you were in it compared to when you know how to drive. If you were in a car chase or another high-stress situation would you be better now than when you started to drive? The answer is you are better when you can use the equipment without thinking about it and the reduced amount of thinking you can do can be for the larger stuff like where should you turn not thinking about how to apply the gas, break, and turn the steering wheels.

Military war games are primarily what you call large-scale exercises they can be just on paper or with just communication between units commander and not everyone out on the fire, The can be with everyone out there too. It is not what individuals do in combat that is the most important but coordination and movement and cooperation between units.

How do you handle moments of there is a limited number of roads? How you maintain vehicles in the field, will break down even in training. How do you make sure units get fuel, ammunition, and anything else you need? Is the communication system working and a forward observer can get artillery support?

How do you coordinate so multiple units attack at the same time and maneuver to support each other?

Making sure everything that is not just individual soldiers fighting is extremely important. If your tanks do not get the fuel they quiclty end up as stationary metal boxes that do not have any electrical power and the only way to fire the gun is to manually crank it around. The ballistic computer and thermal sight will no longer work. The practical effect of a tank with no fuel is as if the tank was not there or destroyed.

It is a cooperation between units and logistics that you train in war games not primarily how individual soldiers do the fighting, that is something they should already know.

When you train troops both on the small and large scale you can use https://en.wikipedia.org/wiki/Multiple_integrated_laser_engagement_system or a similar system to simulate compart by fire lasers that vests on individual soldiers or system on vehicles detect. So you can get "killed" and it out of the fight temporarily.

People like to win and fake combat like that will be stressful even if you are not risking your life. Play paintball, Laser tag, or something similar and you will notice stress and the will not to be hit even if it is all just a game.

If you and your fellow soldiers can do what you should do first with no opponent and then with an opponent that does not kill you for real but take you out of the fight you have a lot better chance of doing that for real compared if you did not training.