> I ran a local NNTP relay on my home phone back in the day. I recall spending quite a bit of time filtering out a lot of the binary groups.

There was a very nice, easy-to-use NNTP server that was intended for small sites with few users, called leafnode. It is in a mature but still-maintained state. https://www.leafnode.org/status.shtml

I ran it on a laptop so I could slurp up my newsgroups and read them on the train with tin.