The only tactical response for Christians, as shown by our Christ Jesus, is to lay down arms and both pray and work for peace.
Obviously, the stakes are much higher for active combatant, and those assailed by enemy forces. My sympathies and prayers are with you. I cannot know the choices you must make. I pray the love and grace of Christ for you.
However, global armchair quarterbacks can easily stop advocating for a war that they have no real stake in. Most plainly, if you are not part of this, do not give easy answers, particularly any that advocate violence.
Thank you for expressing the beautiful sentiments of the historic Peace Churches; I think in the 21st century the human potential for destruction has reached a point where our collective survival requires all denominations to become peace churches to varying extents, in particular based on the tragic failure in Afghanistan to deliver the people of that country from the Taliban after two decades of valiant effort and service, we have to re-evaluate responses to situations, since now, due to incompetent leadership, our military was evacuated from a country, and the same regime that hosted the orchestrators of 9/11, which we had reduced to a mere pockets of resistance, has like a cancer, come out of remission, and once more brutally subjugated women and children, and it seems reasonable to expect it to host the next Islamist man of evil like Al Baghdadi, or Osama bin Laden, or the Ayatollah Khomenei, and a long line of oppressors stretching back to Sudan, where we find Mohammed Ahmed al Mahdi, the first modern Islamic terrorist, who slaughtered the Egyptians and opponents of the self-proclaimed Mahdi in Khartoum, who were failed by Britain as we failed our Afghan allies, although General Charles Gordon chose to die with them as an unarmed Christian martyr, and was impaled while peacefully descending a staircase to meet the invading forces by a spear-wielding fanatic, much like the martyrdom of St. Thomas the Apostle at the hands of a Hindu Rajah in 53 AD.
The real answer is to promote peace through understanding. Apostasy rates among Muslims are increasing, and in the case of Russia and the other former Soviet states that are hostile to us, we need dialogue with them, although by no means can their actions in Ukraine be condoned.
My main concern as a Christian minister in this case is twofold, firstly, to bring peace as swiftly as possible, which in this case looks like a negotiated, but fortunately not an unconditional, surrender by Ukraine to facilitate a peace treaty and the lifting of sanctions, and secondly, to work to achieve forgiveness and reconciliation between the separated brethren of Russia and Ukraine.
Now, I must confess I am not the leader of a peace church; I would, for my part, condone military strikes of the swift, surgical variety, such as that used to discontinue the vital existence of Caliph al Baghdadi, although because he was a coward, he uses innocent boys as human shields and his actions led directly to their tragic death, but for a man responsible for the killing of so many young Yazidi boys and mem, the brutal torture of so many Christian boys and men, who were circumcised without anesthesia, and the rape of so many Yazidi girls and women, such actions were to be expected, but that man will never do that again.
In the case or Zelenskyy and Putin we do not see monstrosity on that scale, but rather, reckless men in the leadership positions of sovereign countries totally devoid of the prerequisite flexibility, patience and humility required by their station, and the tragic consequences of such men being in power. Without full military assistance from NATO, which cannot be provided without risking nuclear war, which is an unimaginable horror, Ukraine can only delay the inevitable, increasing Russian casualties, but at the cost of more devastation of Ukrainian cities, transportation systems and other economic infrastructure, and a loss of agricultural production, the net effects of which will, if the conflict is prolonged, result in poverty and starvation for Ukrainians, which the sanctions against Russia also are likely to cause. This is why we must persuade Ukraine to sue for peace before any more lives are needlessly lost, and any more economic resources are needlessly destroyed.