Ukraine had 10 years of western style training, sent troops to nato countries to learn the experience, so... Nato forces never had such a war, not after 'nam. So no, I'd still say that people who have 3 years of real experience would be better than "just drive around the minefield" nato theoretics
Compared to v2 (the main US M1 mod, btw) the only important difference is the CITV, the A1 has a simpler one with less features for the commander. But that's it
Now, speaking of APS, the one on v3 is already outdated for modern threats. Not bad to have one, just won't save you from major threats like FPVs or mines
When it comes to ERA... They slap K1 wherever they can, so no real difference there
Airburst rounds? Nice feature, even though not a new one. But those entered full rate production only 2 months ago