Glad to see people finally talking about this here! As someone who's very much into and studying politics I'll give my two cents.
Firstly, there's no question Russia can easily defeat Ukraine, their army may be old and fading but it is still one of the largest militaries in the world and vastly superior in, size, technology and capability to that of Ukraine.
As has also been pointed out, the goal here likely isn't really strategic, Putin is getting older and wants to get the gang back together. That to me is really the only logical explanation for invading the entirety of Ukraine. Crimea was strategic but that's already under Russian control.
China has most certainly told Russia not to invade during the Olympics, because Beijing wants these Olympics to be a show of force to the world in the wake of all the bad press they've been getting. Much like 2008, these Olympics mean a lot for China and they don't want the spotlight taken off them. I expect an invasion will come right after the Olympics, like we saw in 2014.
I see very few avenues for peace, Russia is going heavy on the propaganda domestically and knows their demands are unrealistic. At this point they're just forming the pretext to "justify" the coming invasion.
There will be no coordination NATO defence, but it is possible some NATO countries, particularly in eastern Europe who remember Soviet occupation, may send troop support.
The immediate concern is avoiding a global conflict, but spillover is possible, military buildup would happen on both sides of Ukraine and Russia has verbally threatened other nearby countries as well. I don't think they have the intent to invade some of their other neighbors like they do Ukraine, but the more intense the situation the more volitile and mistakes and miscalculations could lead to more parties being drawn in.
That's how I see it currently.