Will a tomboy gg member ever thrive again in kpop like Amber?

Probably not. Especially since traditional beauty is way more important now than it was in 2nd gen.

The closest we had was Miya but WGSN disbanded this year

Big kpop companies need to stop being cowards they would be huge in a big4

depends of what you consider tomboy there are some female idols that are more on the tomboy side off-stage but have a more feminine image on stage, so it's hard to tell but going the amber route is a bit drastic for Korea. I doubt it will ever happen again lol. Maybe moonbyul is the closest and even her isn't as much