Literally is "capture the flag" sort of warfare.
Ukraine are giving a good resistance, but the question is how long will it last?
It's all well and good sending arms, but if you can't get them in, they are of no use.
Re the humanitarian crisis, as part of the talks a neutral channel for aid will have to be agreed to allow food supplies and water plus medical equipment, but nobody could transport arms through this route as it would be seen as a breech of the rules of the aid pathway. They would be transported in Vehicles carrying a red cross, part of the Geneva convention on warfare is that transport vessels/logistics vehicles displaying a red cross must not be fired upon or attacked.
We got in trouble in WW2 when we used a hospital ship to transport active soldiers and arms instead of wounded. Under the banner of a red cross.