Olympiads are olympiads, countries that have strong training centers for such events are usually at the top. The results there do not necessarily correlate with scientific and engineering prowess. For example, it is undeniable that France is a heavy hitter in maths but they are not doing that great in olympiads because there is no system in place for that.
In terms of research and engineering output, we can see that Russia is primarily strong in the fields that it was strong during Soviet times - nuclear physics & engineering, fundamental physics, space, etc. Some of these fields have been stagnating (space) and some are carried primarily by old generation of scientists (esp in fundamental physics), some are still at the very edge like nuclear engineering. Meanwhile if you look at the research & engineering output in AI, telecom, semiconductors, etc., then it is rather lacking. So I think China should seek a win-win cooperation by utilizing Russia's strong points and offering help in the fields where China is at the top.
For semiconductor industry in particular, Russia has rather good optics research, especially in X-Ray optics which would be useful for EUV. On the other hand, China has superior semiconductor fabrication tech. So here are the two areas for win-win cooperation.