I would not advocate sending them east in the first round, but that is because I like to use them to strafe the ukraine. Without that strafe and without defending russian armor in karelia, karelia is actually fairly weak in the first round. I don’t like to bet on germany not being insane, sometimes they are.
However, starting round 2 if I can afford to I will start sending an armor or two east. Again if I can afford it, I may start building 1 a round in turns 3 or 4. Sure it would be nice to rip through japanese forces on the coast, but as you analyzed in another post then you are exposed to the japanese navy. A fine strategy is to let japan in a little bit, say to yakut or sinkiang, and then counterattack. Indeed, I find this to be the best russian “defense”. The problem for Japan is that they have to take territory. As they take territory they cannot defend with planes. So when they attack, they are also defending at 2’s. Russia can attack at 3’s and 1’s, losing the 1’s which are more readily replaceable. As russia, you can even just strafe japan and retreat, then move in some more infantry to your leftover tanks making them a solid defensive force. Then the next round attack again. Certainly russia is going to lose to Japan eventually, but countering japan will slow them down a lot. Note that the above is pretty much just a rehash of deadzones.