So... after almost a week of frustrated troubleshooting, doubting my own sanity and intelligence and almost giving up on trying to run a node at all, my mother happened to casually mention in an unrelated conversation that they never removed the old modem when she switched internet providers.

...

and that's when I realized...

I dragged her downstairs where she confirmed what I suspected; my raspberry pi was connected to the old modem. She pointed to the new one, which is nailed to the wall about 4ft higher.

Everything works perfectly. Sanity and intelligence still in question, but I'm running a #bitcoin #node in my parents' basement now 🤡