Take West Russia with 2 Inf from Karelia, 3 Inf, 1 Arm from Archangel.
I think you mean to add 1 art from Moscow as well, otherwise your attack of 5 inf 1 arm vs 3 inf 1 art 1 arm is pretty shaky. And probably 3 inf from Moscow as well?
I think in general you may be a little thin in the West. Not building any infantry on the first turn and losing 6 of your existing ones, as well as not getting reinforcements from both kazakh/novo, means that about round 3 you’re short on infantry to trade while waiting for the turn 2 infantry build to get to W. Russia. That means Germany is a bit richer than normal, and actually perhaps might push a little harder against you. It also makes it hard on you when you’re using your fighters in the East; Germany is easily using its airforce to sweep away territories while you’re struggling using art and arm to do so.
Jumping down Japan’s gullet may not be as easy as it looks. Japan should just play a bit cautiously - leave perhaps just 1 inf in China when the Russian build-up is imminent, or perhaps stack it with 6 fighters and more infantry to make it impervious to a Russian incursion. It’s pretty transparent to see where the Russians are going to attack, so you should either stack the attack zone with fighters or retreat to a safer position while leaving 1 inf as a deadzone offering.
I don’t think you should be playing 100% defense in the East, but mostly so. You just don’t have the resources to compete with nations on both sides that both have 6 fighters apiece. They can easily out-trade you. You should keep enough forces to keep Japan from coming in totally unhindered, such as keep your tanks in Moscow where they can reach both fronts easily, but any serious attempts at attacking Japan can either be countered by Japan or exploited by Germany on that front.