The definition of "proxy war" is "a war instigated by a major power which does not itself become involved". Regardless of the scale or nature of the aid, since

The definition of "proxy war" is "a war instigated by a major power which does not itself become involved". Regardless of the scale or nature of the aid, since Russia is directly involved, the Ukraine war can only be a "proxy war" if you believe it was instigated by the EU/NATO/the US, which is essentially assuming the Russian talking point that it was somehow forced to invade Ukraine because it felt threatened. I disagree with that position and if you do to please do not describe it as a "proxy war" even if you think that other countries providing a limited amount of aid rather than getting actively involved will cause the war to be prolonged.