Can Your Broken System Let Me Go Home?

After traveling through time and becoming a city lord from another world, you are bound to a "hell-level war system" - if you fail the mission, you will be wiped out. If you complete the mission... You will be given the next round of hell-level missions. The protagonist has only one goal: to accumulate enough points to exchange for an "escape coupon". This is the only way to return home. But the "primary mission" assigned by the system is: use 10,000 militiamen to annihilate the 300,000 Iron Heel Legion within one month.