many mid-20th century French thinkers like Foucault, Debord, Deleuze and Baudrillard spent a lot of time writing about surveillance and technology. Lots of this stuff has turned out to be extremely prescient. (Ellul is another example, but as a Christian Anarchist his critiques of what he called the Technical Society, are a bit of an outlier from the other guys above who, despite a plurality of ideas and perspectives, were all coming from a pretty similar place wrt their philosophical backgrounds)
A pretty easy to digest example is Deleuze's "Postscript on Societies of Control", which is like 5 pages long and available for free online, written ca 1990 that is pretty spooky in how accurately it predicted the current state of affairs.
The real king here is Baudrillard but his writing isn't always the most accessible
his book on propaganda, The Formation of Men's Attitudes, is also well worth a read.
I think his ideas on concentration camps/prison camps slot in nicely with Deleuze's ideas about Control Societies and the ways that technology is being used to extend the Foucaultian ideas of discrete enclosures to never-ending enclosures in all aspects of life.
And, if you like Ellul, you should definitely check out Ivan Illich's work. He's another social critic coming from a heterodox Christian perspective (Catholic in this case). His ideas can seem a bit unintuitive at and even off-putting to modern sensibilities at times (especially his idea of Life as Idol and his critique of modern medicine in general) but he's another guy with a lot going on that has been pretty accurate in his prognosticating of contemporary society.