Without going too deep - as we would never get out - it is worth noting three things.
First: in the Treasury's just released report on FX manipulation, neither China nor Russia were accused of devaluing their currencies. If Trump has a problem with Beijing's or Moscow's FX policies, he should probably first instruct his treasury.
Second, both currencies have been strengthening for over two years, and only saw a modest loss in value just very recently.
Third, the only reason Russia is "playing the devaluation game" is because of the sanctions Trump unleashed on Russia last week which sent both the ruble, and Russian assets crashing. If anything, Moscow wants a stronger Ruble to avoid having to raise rates even higher. As for China, while it may want a weaker yuan to boost exports, it will surely come as news to Beijing that it is devaluing the currency, which is trading at the strongest level against the dollar since the August 2015 devaluation, as a result of - drumroll - the weaker dollar. In fact, the weaker the dollar, the stronger the Yuan.