Quote: As for the the claim that the conflict is a “proxy war”: since 24 February Russia has used no proxies. The charge of waging “proxy war” can only be levelled at Ukraine’s Western supporters — including the USA, NATO and the European Union. Its effect is to deny Ukrainian agency

You have this half right. This is in no way a PROXY war-

A proxy war is an armed conflict between two states or non-state actors, one or both of which act at the instigation or on behalf of other parties that are not directly involved in the hostilities.

Russia is a principle in the war.

An example of proxy war would be if we supplied Ukraine who would be at war with a Russian supplied Belorussia.

Supplying Ukraine with weapons and support does not make it a proxy war on our part any more than China supplying materials to Russia makes it a proxy for them