Hiya @caiahat !
Um, wow. While I am complete and utter anime trash, I’m also very much Euro-trash (I, uh, don’t live in Japan 🙂 )
However, I think I can give you some indication as to Yuri’s popularity in Japan if Kubo’s Twitter is anything to go by; The original creator of the show tweets exclusively in Japanese and has like 270k followers. The sheer love and attention anything about Yuri!!! on Ice gets, certainly gives the impression it’s a popular show!
For some more info on Kubo’s tweets: