They get a far weaker Russia much more dependent on them now economically. Russia is rich in fossil fuels which China lacks and has some advantages in defence and space tech which China can easily get their hands on.
CCP might not be that confident about taking Taiwan now but they get a massive economic boost and a possible big brother relationship with Russia now.
I can’t claim to be an expert, but it seems pretty clear to me that China’s action or inaction on Russia will have huge implications on their next decade and beyond.
Russia is inconsequential compared to their trade and economy but not clout.
But looking at the overall figures is just partial picture. China imported over 10M barrels of oil per day last year. [1] At current prices of Brent, i.e. an import bill of $1.4 billion per day or $500 billion per year. Imagine getting a discount on that.
Also, Russia still has tech advantages over China in some areas, the best fighter aircraft in PLA's force uses Russian made engines. They rely on Russia for their Air defense systems, the S400.
[1] https://www.reuters.com/markets/commodities/chinas-crude-oil...
That is only if they would realise it, if the Russian propoganda works at home, China might be the only true friend they have in the tough times to come.