Considering US has technological lead, reserve currency, workaholic culture, giant capital, reserves of raw materials and large population the only country that can challenge US is China.
I have a sneaking suspicion that a lot of the leadership and capability is far more precarious than many believe. Might is actually myth. If you remember it was only a couple years ago that the might of the Russian army was to be feared globally - is it still the case?
Europe should become more self sufficient and less reliant on US so that it can at least defend itself or else it risks being quickly overrun by Russia if it manages to defeat Ukraine.
I suspect this isn't possible, unless Russia are willing to go nuclear. And in that case, we are all screwed globally. Europe isn't quite as unprepared as the the people of the US are led to believe, and when push comes to shove, they will gather. The EU has 450 million people in it - with many willing to push back.
I think you are overestimating the strength of combined European forces at the moment. Here is a good analysis of this issue: https://www.bruegel.org/analysis/defending-europe-without-us-first-estimates-what-needed
At least 300K more troops and a Major production surge in equipment to stop Russian invasion of Europe...
The numbers don't tell everything.
For instance, Finland has a population of only 5.5 million and a military force of 24,000. However, in wartime, it can mobilize 280,000 soldiers, and have a supply of 900,000 reservists that are military trained. Because in Finland, military service for men is compulsory. Yes, this isn't a full-time professional army, but don't underestimate how many could mobilize across Europe. As said, if push comes to shove, Europe would push, in a similar fashion to what Ukraine has done the last few years. It wouldn't be pleasant for anyone.