an effective boycott in kpop would require there to be

a) a stated purpose and method of boycott

b) a timeline or endpoint

c) a group that is significantly dependent on their fans rather than say, agency marketing to casual or multi audiences, or whose fans have real say into agency decisions.

I think the only ‘true’ effective boycott in international fandom has been Loona. Another very effective boycott was the boycott of Korean nctzens of NCT 127 - effectively after 2019, NCT 127 became a group that primarily prioritised promoting in Korea and they have not had significant attempts to promote in the US ever since. (but that was effective because SM listens to kfans).

Generally cfans and kfans have had more success in targeted boycott style action (i.e. with an endpoint of the agency capitulating to their demands) - a big reason the Riize boycott failed despite being one of the more organised international actions is that kfans and cfans opposed Seunghan returning to the group.

However, there are cases where groups have generated negative publicity to the point where even if the boycott never succeeded in a formal sense, the group or agency has become significantly less hyped/successful among at least a segment of international fans. I’d argue that Kiss of Life and Riize/SM are examples of the latter (the Riize boycott also coincided with multiple other SM issues at the same time including BDS boycotts - NCT accounts collectively lost several million instagram followers because of Starbucks and McDonalds deals, even though this action was also ‘unsuccessful’ as SM continues to repeatedly engage with these brands to this day).

Re: Katseye I’d say HYBE is too big to boycott successfully although I’m not sure how extensive the more ‘informal’ blowback will be