I do have some doubts about the morality of the west outsourcing a war with Russia to Ukraine. For me, those doubts are small as long as Ukrainians are successfully fighting back and requesting the assistance we are providing (and more that we aren't willing to provide). If the war goes bad for Ukraine, though, what does the west do? If we're going to not intervene and allow a (doomed, IMO) Russian occupation, then I'm less certain that what we are doing now makes us a good ally.
The west didn't outsource a war with Russia. Russia invaded Ukraine, Ukraine is resisting. The rest of us cannot intervene because Russia has nuclear missiles.
Nuclear missiles mean that a conflict between NATO and Russia would probably escalate, it would be almost impossible to prevent escalation once one side started losing. Escalation in a nuclear confrontation means the end of the world, full stop.
I am rooting for Ukraine 100%, I am donating money to the UNHCR and Red Cross, and I think they are going to win. I do not and will not ever support NATO getting into a shooting war with a nuclear power because then we all die.
Finally, we in NATO are not allies with Ukraine. That's the whole point - Russia didn't want them to join NATO. We have no treaty obligations to Ukraine, which is a good thing because if they were in NATO and Russia invaded it would be WWIII and we all die.
We do have moral obligations because the invasion is a monstrous act, and we need to help where we can without making things worse. Escalation to a nuclear conflict is unambiguously worse in every way than the current catastrophe.