Ukraine has spent almost no money on its armed forces.
Well... Germany and France could afford to be armed to the teeth if they’d back off a little on the whole socialist / green thing. (Is Germany still limited by post WW2 restrictions?)
Suggestions for the West (I’m sure others can think of more and / or better):
US / NATO countries to initially provide arms, also provide reasonable terms loans and / or subsidies for Ukraine to divert entire arms production to self, in return for mineral rights (leases), and “severe” (and enforced) anti-corruption measures, along with market reforms.
EU to commence major(!) pipeline projects to Qatar and Saudia Arabia; at least some of these can connect to Ukraine gas pipeline network. US, Ukraine, and EU to provide expertise and manpower to assist SA and Qatar in ramping up gas production as fast as possible. NATO and involved nations to provide security (will NOT be easy.)
US also to provide expertise / assistance for Ukraine to develop remaining petro reserves as possible, plus look for new discoveries.