What happened to secular, non praciticing/non relegious jews and fake converts during the holocaust? Any examples?

I'm not Jewish. Just in Germany right now visiting various holocaust memorial sites. Have a background where I went from traditional orthodox to cultural non practicing Muslim. That's not nearly as much of an established thing as being a cultural jew is but nonetheless. One thing I'm realizing visiting these places is when radicalism take holds it really doesn't discriminate as long as they can label you the "other" and scapegoat you. All the nuance pretty much goes out the window. Another thing I have become aware of is that things like the holocaust aren't really a one off catastrophe. They can happen again if the conditions become as such which in the west seems increasingly so with worsening inequality and deteortiating economic conditions.

It's made me wonder what happened to non practicing jews in the holocaust?

What about fake converts who converted to Christianity to save themsleves. Did either of these help in any way and are there any known examples of people in this particualr situation?

Also if there was ONE thing that saved jews or helped them the most to escape this catastrophe during this time what was it?