Almost none of the people on HN have anything to contribute to the Ukranian military. At the same time, all of the things related to actually living as a person in any country, at war or peace time, revolve around jobs, the economy and technology, things people on HN have a lot to do with.
https://ukraine.ua/news/support-the-armed-forces-of-ukraine/
If you want to donate I would try to find some small scale relief effort that probably has no free Central bank money raining over it.
Given the success of Turkish drones against older Russian weaponry during the recent conflict in Artsakh, maybe the Turks could be convinced to test the drones against more modern versions? Although your point is correct, that the time to have arranged this has passed.
https://bank.gov.ua/en/news/all/natsionalniy-bank-vidkriv-sp...
Many people here could participate in their cyber efforts, and/or know others who could. I would think HN would be an especially fruitful recruiting ground.
Also, public support worldwide is essential, as is evidenced by both sides' intense investment in it.