If she accessed Instagram from the same home network (and IP address) as her main phone, the zuckerbots inferred that the two users were probably in the same household and knew each other/had similar interests.

You can have those in the fediverse on Pixelfed and Mastodon. The problem is that then the people you can follow are only middle-aged Linux/Star Trek nerds and the occasional organic farmer.

Beulah, Eggstone, Lacto-Ovo, Mid-State Orange, a lot of bands on a German label named Apricot Records

Late-90s/early-00s-style lo-fi indiepop with glockenspiels/Casio keyboards (or similar cheapass-sounding synths with a nicely skronky/angular timbre) and the odd trumpet/brass section

Danes, or as they’re called in America, Lego Germans.