You may want to read Dies the Fire by SM Stirling. Read it about twenty years ago, enjoyed his exploration of that same idea. I don't recall any pausible explanation of how explosives were nullified, but many details of the book elude me atm. Being a pointed sticks guy (i.e. humans can't really be trusted as a species with anything beyond pointed sticks), I will follow your inquiry with interest.
Sounds like the Hard SF end of the spectrum. Good place to be! I notice, when browsing the fiction section of a library, that there is a cluster of really good hard SF authors under the letter B. Stephen Baxter, David Brin, Gregory Benford, Ben Bova, Greg Bear, couple others. And of course Arthur C. Blarke! 🤔