Dude, it's not the United States fighting against Russia here. It's the Ukraine military, which is held together on a shoestring budget with donations from NATO. The Ukrainian armed forces military structure is based on Soviet doctrine, with large parts still reflect the Soviet era force structure. Little has changed since then, although they have adopted in NCO structure like you see in NATO forces.

However, many reports out of NATO in the United States have pointed out that Ukraine armed forces still have a long ways to go before they can be ready for NATO integration. Not to mention that the huge variety of equipment that they are currently running, which includes massive amounts of Soviet era weaponry armor and aircraft, on top of a hodgepodge of NATO equipment simply exacerbates their issues.