My (great)-grandparents were part of the Dutch resistance during WW2. Along with a full 1.5% of the population.
Most people will not do anything, even if they are literally rounding up people for a genocide.
On the more positive side, a lot of people will support the resistance in small ways.
The number of people who actually, whole heartedly collaborated with the Nazi’s was quite small.
Even some of the German soldiers stationed in their village would turn a blind eye. Some of them realized they were on the wrong side and they just did the bare minimum of what they needed to do to not get in trouble and not get killed.
I think that they were winning before they invaded the Soviet-Union.
In an alternate timeline where they kept the alliance with the USSR, I think they would have won.
The USSR had resources while Germany had engineers and technology.
And without an eastern Front, they could have held off the allies on the western front.
But they got cocky, paranoid and greedy.
And I am glad they lost.