I think very few, if any, countries in the world would be stronger than what we turned Ukraine into. You have a massive army being replenished by a constant slew of bodies, to the point of forcefully dragging people in off the streets, and then being armed with hundreds of billions of dollars in Western arms. But what gives Ukraine a particular superpower is their logistics.

Most people don't realize is that war is essentially a giant deadly game of logistics, and so the typical plan for Russia would be to simply destroy the logistics pipelines arming Ukraine. But thanks to the people 100% responsible for maintaining Ukraine's military managing to maintain a strategically accepted neutrality, it's impossible to fundamentally disrupt their logistics pipeline outside of small scale black ops stuff.

So that has turned this war into a war of attrition where Russia is advancing slowly, but mostly setting the goal as essentially having Ukraine simply run out of Ukrainians. And they seem to be succeeding. Once the real death tolls for this war are revealed, people are going to be shocked. You don't need to drag in people off the streets, close your borders, and continually lower the enlistment age (in a country with a severe demographic crisis) if you're not suffering catastrophic losses, especially since as the amount of territory you have to defend decreases, you need fewer soldiers to maintain the same defensive density.

China hasn't started a war since the 1970s.

Okay, as Devil's Advocate, you could say the same about the US. It was unable to conquer Korea, Vietnam, Afghanistan, Iraq or Syria.

America is on a isolation downward spiral.

Russia will conquer Ukraine, any other prediction at this point is absurd.

See point one, America is alone now, it will take decades to repair the damage.