China doesn't think in that way. It doesn't make permanent alliances. It is always open to reach limited, scoped deals in fields where it benefits them.
Yeah that sounds like a pretty good deal. Drop the bankrupt Russians and do a deal with us Europeans, a much richer market, to brace against US economic warfare.
I suspect that China might be Russia's Ukraine offramp. If Russia decides to pull out, China can come in and work as a negotiator and win brownie points with the EU. I could see them being able to continue working with both Russia and the EU in that future.