Then the EU is working on lowering gas and oil consumption

this. both crude oil and gas consumption in eu have been decreasing during past few years.

In theory they could start trading predominatly with China instead of EU ofc.

the question is, would china want to import from an untrustworthy partner? afaik china isnt very dependent on russia. china is more oriented towards south korea, european countries, usa, australia, etc. plus russian market is not very lucrative, with its low purchasing power (poverty) and low trust (economical blackmail and conflicts with lithuania, ukraine and others).