Putin will more then likely not be around, and he probably figures if he regains the territory, it will be worth it in the end, regardless of how many decades it takes to economically recover. Russia’s demographics were such that it was a make or break time. And his fumble in Ukraine seems to have made it a fumble.
I hope India learns the lesson from this war that any war with a determined western neighbor won’t be a cakewalk and will cost them dearly, which is why I hope the Ukrainians make the Russians pay for every inch of Ukraine they take, even if ukraine seems to “lose” at the end of the current hostilities, because eventually the Russians will have to give back to get sanctions relief. Also, that Pakistan is not as weak as Ukraine and India is not as strong as Russia.
Putin is proabably hoping Chinese companies will invest in Russia, to pick up where Western investors left off. Not a bad idea, especially in civilian industries. China should be careful lot to help the Russian defense industries.
China could also use this conflict to extract concessions from the Russians, such as allowing the PLAN to use the Vladivostok Naval base and Sakhalin Island to get around their first island dilemma, as well as greater incidence in Central Asia, and to allow China to build a corridor between Turkmenistan or Kazakhstan and Azerbaijan to allow BRI back on track (outside of Russian territory)
If China is to be of any use to Russia, China will need ways to insure its economic growth, and the continuation of BRI is vital for that to happen. A Chinese owned trans-caspian rail tunnel would be a game changer.