Ok I think the problem was somewhat fixed and I don't know why.
I read into the problem a little bit more specifically for Linux and fond that in earlier versions you had to install libu2f-host0. After installing it Opera still crashed. I came back to the problem today and it just worked somhow. I don't know why exactly especially since I restarted Opera multiple times before and after installing libu2f and I don't even know if libu2f was the problem. But somehow it just worked today. Weird.
