First of all, if you didn't mean to imply it that's one thing, but it is clear to me that "Depends on if the invaders plan to genocide the people or not. The threat of genocide should influence a leader to fight. The cost of genocide outweighs lives lost in conflict." implies that whether or not you should fight an invading force "depends" on the threat of genocide. The word depends in this context means that the outcome will be different if there is or is not genocide. So let's not say that you DIDN'T imply it because you did. Misspeaking is fine, misrepresenting what you said after the fact is disingenuous and reduces your credibility in my eyes which makes it harder for me to engage in a meaningful way with you.
Now that we've established that you believe that fighting back against a hostile invading force is a reasonable course of action you have moved the goal posts back to claim that while fighting back (which Ukraine is doing) is fine, the fact that you view them as dependent on foreign countries to support their ability to fight means that they shouldn't fight back? Clearly it isn't a gamble since Ukraine has been successfully defending for nearly a year and a half. Of course they are also losing lives in the war, but not only are they losing lives at a FAR lower rate than Russia, but even in your perfect hypothetical where a country is invaded by a hostile force and can successfully defend without receiving any aid from any outside sources, they will still lose lives in that successful defense.