Of course they have agency. Many, perhaps most, of those who have been allowed to have fled the country. It is of course their right to stay and fight for anything they believe in.

When I say I don't think it's in their best interest to do so, and that I think they are misjudging Russia's determination if they believe they can win, I'm not taking away their agency. As such, I don't believe my leaders are doing them a service when they are supplying them with weapons and military intel, and if it were in my power, I would stop this supply (all the leadership, and the vast majority of the public, in my country is almost rabidly anti-Russian and pro-NATO, so this is an extremely theoretical exercise).

In the end, I believe NATO is playing chicken with Russia, but putting Ukraine in the speeding car instead of driving it themselves. I don't think this is wise, and definitely not good for Ukraine.

I just cant grok that viewpoint. As an American the French did the same thing to us in the Revolutionary war that we are doing to Ukraine, i.e. supplying arms to another nation to fight a proxy war against their enemy. Even while knowing that and with the benefit of getting to peruse historical documents rather than figure this out pre communications technology, I still appreciate that they stepped up and helped us when we wanted to fight. I can't imagine the Ukranians as being any different.