I agree with your point overall but realistically speaking, its not like the death of Ukraine will fix Russias economy, even if it did: not in a single day.

You can exhaust yourself completely and be dead on your feet.

Doomed, is the expression.

Ukraine is also very hard to completely destroy, either militarily or economically. And Ukraine is in an existential struggle, I don’t see the Ukrainians caving.

Every day that passes, Ukraine gets stronger: more domestic defense production of what's currently the cutting edge of warfare; deeper financial integration and relationships with Europe; more aid lined up; European powers taking more responsibility for supporting Ukraine and seeing it win, not just survive. They have the largest and most competent army in Europe that's fought Russia to a standstill.

Every day that passes, Russia gets weaker: more oil sold in crude form only, since they don't have refining capacity to export gasoline; foreign currency reserves shrinking, since China is their main customer; another 35k casualties every month, with mounting costs for enlistment bonuses and death benefits; outer provinces stripped of men of fighting age, North Korea unwilling to send more soldiers, African recruits drying up; inflation raging, industries shutting down, and all economic indicators heading south.

It's terrible that Ukraine is trapped in this slugfest, but at this point, time favours Ukraine.

But then what, become a part of China? I don't think Russia could defend themselves from an attack of a lesser nation right now, and I truly wish one of them would take opportunity

Why do you imagine Ukraine's desire for sovereignty would be exhausted before Russia's stomach for economic hardship? Do you really think the Russia public has the stamina even for the 4 more years it will take them to capture the rest of Donbas?