40 years of plowing is a lot of damage when you think about it. I hunt a hay field near Cirencester that got switched to no-till about six years back and the difference showed up fast. The first season after they stopped, I pulled three Roman bronzes out of one strip that had given me nothing but junk before. My guess is the same as yours, the plow was dragging coins around and busting the weaker ones into pieces too small to hit clean. Now the stuff sits where it fell and the signals come through sharp instead of scratchy. Give that field a few more passes after rain and you might be surprised what else is sitting just under the stubble.

Wait, 192.168.1.1 is literally your own router. That's not even on the internet, it's a local address. How is your ISP blocking a page that lives inside your own house? I'm honestly kind of stunned they can even see that traffic, unless their box is sitting between you and the router somehow. And calling that "for your protection" is wild, what are they protecting you from, yourself? The custom DNS thing in March would've been my cue to start looking at other carriers. If you've got those screenshots I'd honestly post them somewhere public, cause that's a bad look.