God does miracles; Angels use technology. God drowned EVERYONE and EVERY THING with the flood. The fallen Angels brought Nephilim back to the Earth to spite God.
I have no doubt spite, was one of the reasons, but there may be other reasons too. I don’t think the fallen angels spawn the Nephilim today, the same way they did before Noah’s time. As you say, they use technology. I think they have used so called “alien abductions,” which I think has been going on, since after the Flood. What are they doing now? I don’t know. I am sure they are up to no good, however.