Ukraine of 2014 and Ukraine of 2022 are vastly different countries. In 2014 the military was really for show, whereas now they are battle hardened thanks to being at war with Russia's proxies for ~ 7 years. In 2014 the population was soft, whereas now a significant chunk of the civilian population has existing militia training, or has signed up for it. I saw somewhere the statistic was 30%, but it wasn't government published so grains of salt required. Regardless, the levels of their population identifying as Ukrainian instead of Russian has boomed, though some of that might be out of fear of persecution. 

What 2022 Ukraine desperately needs is political weight brought to bear (which is a work in progress, Germany and France seem determined to keep shooting themselves in the foot) and more military hardware. There's been tons of military hardware being donated from all NATO, plus they've been steadily shopping for hardware over the last 7 years. 

Russia will still steam-roll them, they just have so much more manpower and hardware they can bring to bear. Additionally, once Putin presses the go button he can't afford to lose, and he can't afford for it to drag on long enough for the western nations to be forced into action by their constituents and treaties. So if at any point it looks like they're losing or it's becoming frozen I would expect Putin to seriously consider the use of pocket-nukes; it's a tactic Russia has in their military doctrine (escalate to deescalate) for which Ukraine has no counter and NATO is ill equipped to counter either (NATO has lots of level a city or county nukes, but very little tactical level warheads that only vaporize a few city blocks).

If this happens it's going to be painful for Russia both in the short and long terms, and that's before you factor in sanctions. It'll be another Afghanistan for them, rather than like Crimea or Georgia. 

EDIT: Dumb word choice