Ukranians will fight, but in the end they will fail. It may take weeks, months, even years, but Putin won't stop until he has Ukraine. Everything we've seen in the past from him shows that he hate showing weakness, he hates not getting the outcome he wants and he will do whatever it takes to get there.
The only way to stop that is if the west provides enough to counter Russia's superior military capability, particularly in the skies, but it doesn't look like they'll even provide those jets Poland wanted to send. So in the end Ukraine will fight nobly, Ukraine will fight bloodily, and Ukraine will fall. They will lose a lot for nothing.
At that point you would wonder if it's simply better to just give up and accept your fate instead of all the bloodshed. If the west doesn't want to get involved due to the risk of nuclear warfare then there is no outcome other than Ukraine falling. And other non-Nato European countries will likely be next if Putin lives long enough, Maldova is almost certainly guaranteed, and Finland and Sweden are very feasible targets as Nato wouldn't get involved. The only saving grace is that Putin is already quite old. Had he been 10 years younger you'd almost certainly be looking at further invasions, and the question you'd have to ask is at what point do you intervene to stop the madness. Instead it looks as though Ukraine won't be the Czechoslovakia of WW2, but rather just a sacrificial lamb.