What's the Biggest Challenge in the War on Terror?

It's not clear what's going to happen with the Russia strike campaign and how that's going to affect Ukraine over the winter. I think there could be policy change on provision of certain capabilities, which could change the trajectory of the war at least at the tactical level. For Ukraine, near-term, it's ear-defense and ability to maintain pressure on the Russian military while reconstituting their own forces. On the Russian side, I think it's artillery ammunition is going to be a major constraint.