Ukraine, a poor medium sized Eastern European country, equipped with old Western equipment and Western intel (Palantir, advising, etc.) is currently fending off what many claimed to be the 2nd most powerful military on earth…Russia. With no US boots on the ground.
What if Russia had rolled over Ukraine, formally annexed Georgia, Khazakstan, your favorite MOLDOVA, and a few more such states? Emboldened and with an Alliance with China, it's Russia against Europe and China launching ships and missiles at Taiwan.
This was a fear of NATO for a while, and a legit one. Why do you think countries like Estonia, Latvia, and Poland joined? They hate Russia - that's why. It's why Turkey and their Muslim politics would rather be pals with France and Germany than Russia. Finland and Sweden? They saw the Ukraine situation and said fuck that, we'd rather be safe than sorry.
The Russia that is bogged down in Eastern Ukraine right now is not the Russia of that timeline. It is severely, severely neutered. And, even in that timeline, Russia would likely have done some half assed plan. But US and NATO soldiers would be doing the fighting and dying.
China is watching with fascination and learning a lot, just as the US and friends are. India too - they buy tons of Russia military shit - the kind that is going poof and gurgle against quite basic and old Western shit. And cheap Ukrainian sea drones, which are proving to be a BIG problem for the Russian navy.
Encouraging or trivializing territory expansion from Russia is bad US foreign policy. It just is.
These guys leveled Grozny and their Muslim population in the 90s. Supported Serbian craziness too. Invaded Georgia in 2008. Took a bite out of Ukraine in 2014 while Obama watched with his thumb up his ass and did nothing. Merkel and the lot too.
In comes Trump. Don't fuck with US, and pay up NATO, is made official policy. Iranian generals go poof. Putin doesn't do shit.
In comes Biden. Feeble. Internationally corrupt. Buddies with China and Ukraine, but doesn't really have much teeth. Abortion of a withdrawal from Afghanistan.
Hey, why don't we invade now? Says Putin. Shit will be easy, Ukraine really doesn't know what they are doing and our airborne troops will surround their capital city.
Two years later, even with sorry ass Biden in office, and Russia still is fighting tooth and nail for some towns on the border at huge losses.
All of this TL,DR shit is to say that Russia was taught a brutal lesson in the difference of NATO training standards, equipment, and command structure - even when the actual soldiers are Ukrainians empowered by centuries old hatred of Russia.
Hell, most of the initial Ukrainian troops weren't even NATO trained. They just happened to have this amazing 80s tech called javelins. The Russians are the ones deciding miles long columns of tanks and fuel tankers was the way to go.