As for the "dislike an artist and I'll dislike all artists with the same name", you could theoretically compare the two by artist-ids, which you can see when sh

As for the "dislike an artist and I'll dislike all artists with the same name", you could theoretically compare the two by artist-ids, which you can see when sharing the artist through the Spotify client or using a browser to show the profile. Spotify usually doesn't just give the same ID to several artists with the same name, but of course it's not impossible.