No, it's because of renewables. Share of oil in total energy consumption hasn't increased since the sanctions, while wind and solar have been consistently increasing. Coal is down (again, as a share of total energy consumption).

Source: https://ourworldindata.org/profile/energy/china

China is trying to eliminate oil because of the Malacca Dilemma. The US and allies control the seas as part of containment policy. The US also has the Middle East on lockdown, every gulf country in particular. China has a little base in Djibouti and influence over a collapsing IRGC I guess, but not enough to secure any routes. China only has land-based power projection in Eurasia which exerts some limited but insufficient control over land corridors. This is the real incentive behind China's renewables and electrification efforts. That it also addresses global warming is a very welcome side-effect.

No.

Re: China, see: [1] which goes into some detail. There's also various IEA energy reports which anticipated a fall for India and China after the fall in every other country (save, apparently the US which is bucking the trend).

China is also getting coal from Russia at rock bottom prices. Coal is no longer cost efficient source but for a big country like China shifting away will take time.

Most of the Russian Oil is refined and ironically a lot exported to Europe.