I have a suspicion that Apple Music just decides the next song based on the previous one that played, not your whole playlist or even the last n songs played.

I guess you get what you play, none of those songs are recommended to me, and my Discover Weekly has maybe ~75% of music I like which is high enough to be useful for finding new stuff. But then I have been using Spotify for almost 20 years, might be why they're a bit better at recommending me music.

But then you also consider other people's music taste "basic" so we already know you're a bit of a elitist music snob, no wonder recommendations don't work for you :)

Weird, or maybe website author sorted it by song's popularity?

Even if they are "legit", we don't know it's actually them who listened to it. I'm in the car with other people plenty of times, and listen to music I'm not a huge fan of but others are. I'm sure I'm not alone in not being 100% exclusive listener to the music my Spotify account ends up playing.

I think it's the typical "average stuff for the average person", people generally don't care that much about what music is playing, as long as it's within the range of "average" and it's catchy enough. Basically open up the player, play the first thing that looks good enough and then leave it there.

Then it's called "mainstream" music for a reason, most people are OK with listening to it in the first place :)