[SunshineSlayer]

I would recommend that you check out Superfly since you seem to primarily be into female solo artists. She is basically the only newer solo artists I've really been able to get into. And even she now debut around 10 years ago-ish. But she is very well liked in Japan and very talented.

The music scene, especially for solo artists, has disappeared. Nishino Kana, while popular, is not anywhere near the likes or Ayu or Namie at the height of their popularity. Artists like Namie and Ayu have had far longer shelf lives than solo female artists have ever had in Japan, due in part to the fact that just no one else has really super broken out since them that could really compare.

Watching music specials these days is just sad. Nearly the entire performer's list is made of either an AKB48 related group or an Exile related group. And I actually like several boy bands and idol groups in Japan, but dear god is it stale and overdone now.

And just to throw a counterargument into here regarding the popularity of idol groups and it just being a passing trend: There hasn't been a time in Japanese pop music that there wasn't some wildly popular idol group. And in the 90s to mid 2000s, the most creative time in J-Pop by most counts, it was Morning Musume. But even they in that period did not have typical idol sounding music. It was wildly musically creative, which is why you still hear songs like Love Revolution 21 and The Peace, etc. But now, everything is just so samey sounding. It's really boring to watch a music show these days. It's really unfortunate.