Preventing Ukraine from exporting grain not only causes suffering to the Ukrainian people, but also causes a crisis in many countries that need these grains.
Not only grain, there are many other necessary materials. Here in my country, for example, we suffer a lot from the high prices of some materials such as oil, iron, and others that were imported from Ukraine.
You make a valid argument concerning the human cost of war. Beyond the immediate loss of life, war may have a catastrophic effect on a country's economy and infrastructure, resulting in long-term issues such as poverty and instability. And, as you indicated, the consequences of conflict can extend well beyond the borders of the countries involved. The blockade of Ukrainian ports has not only resulted in food and other supply shortages in Ukraine, but it has also pushed worldwide prices up, putting millions of people at danger of food poverty. So, if these demands are not addressed, it might result in a prolonged period of instability, with far-reaching ramifications for this entire area as well as the rest of the world.
All stated here in this contest is of reality about war and it's consequences, war is the most dangerous engagement to occur in the means of human existence as it effects never tells good but only destroying the human struggle and their achievement.
Allot has to be corrected and restrictions need made in certain area of life during with a clearly defined terms and conditions, what is happening today all over the world where nation are deprived to export or import grain and other items is as result of unclear terms during war. Another necessity is taking sanction on defaulter of the laws without taking sight of fear against any who violated it. This issue is not only between Ukraine and Russia but also in the case of isreal and Hamas the supply of grain and others items has become a problem as those acclaimed to have power over the others uses it as weapon of war to course starvation and losses in their opponent.