China is just an ally of Russia in this war, but is playing a game because it cannot openly ally with Russia lest it get sanctioned. It cannot openly give Russia weapons and supplies, either, so it lies and tries to hide it:

China North Industries Group Corporation Limited, one of the country’s largest state-owned defense contractors, sent the rifles in June 2022 to a Russian company called Tekhkrim that also does business with the Russian state and military. The CQ-A rifles, modeled off of the M16 but tagged as “civilian hunting rifles” in the data... Russian entities also received 12 shipments of drone parts by Chinese companies and over 12 tons of Chinese body armor, routed via Turkey, in late 2022, according to the data. https://archive.is/mxH2H

The reason China is calling for a ceasefire now is because Russia wants them, and Russia is laundering its request through China to save face.

And the reason Russia wants them is because it is nearing exhaustion for its "offensive" of these past 2 months, which has achieved little in terms of gains, but has resulted in enormous losses of Russian men and material, most famously around Vuhledar, but also around Bakhmut. Russia's front line units are depleted and weak, and there are wide media reports of a coming Ukrainian counter-offensive. So now would be the perfect time for a "cease fire" to allow the Russian units to resupply and absorb more mobiks.

Which is why it won't happen, of course, but Russian propagandists will make something of a show of being agreeable to one as a propaganda tactic.