Great question! I am upvoting! Also just want to say that I am very sorry that Ukraine is left alone and as a Polish citizen (now living in London) I will try to help in whatever capacity I can. My friends are already helping in Poland with transport and housing for refugees. We stand with Ukraine! We are very sorry that the World is just standing and watching this, we hope there will be more sanctions and weapons delivered soon.
And yeah I join your problem - also not sure what are the best opportunities to donate to. So far I supported Polish Humanitarian Action, because they already were helping in Ukraine, so they know organizations on the ground, and they are respected and trustworthy (they helped in many war zones since 1992, including Syria, Iraq, Afghanistan or Chechnya). However, I would like to donate to a Ukrainian organization but it's hard for me to understand where is the best place to donate.
I will however support Ukrainian refugees directly. Either with money, transport, or housing in London if needed.
All the best to you! I hope your friends and family are safe!
I wonder about the issue of how cost-(in)effective current interventions really are - it's true, that current interventions in the war zone can seem cost-ineffective in terms of immediate help to affected populations, however there is one larger game at play - Russian Federation's (and Belarussian) aggression against Ukraine effectively demolished the current peacekeeping balance in Europe and across the world, and it seems that responding to worldwide defence challenges in case of Russian victory can be much more costly and time/attention consuming, than in case of Ukrainian victory, see a possible analysis here:
Therefore, it seems to me (curious to hear your thoughts), that supporting Ukraine's defence/humanitarian response, even if seems less cost effective at the face value than other possible EA actions, can actually save a lot of money/time/attention in the long-term perspective (not sure how to quantify how it exactly measures up to other existential risks etc., but my first reaction is that with new Cold War going on in case of Russian victory, responding globally to any other existential risks will be much more complex and difficult - however, how one's indivitual contribution/donation plays into all of this is one tricky question).