I dont know anymore, jyp being trash is for sure a part of this, they being scared shitless of china so they avoid anything related to taiwan if a factor too.
But even if this sound crazy she probably have some responsibility, the twice girls have said lot of times most of their schedules are shared on a group chat and the ones that want to do it are the ones that respond faster, so some of them can avoid doing some things by simply ignoring it and letting others respond first. So they have lot of input in the schedules each one do, for example in album music credits where tzuyu have less than the rest you would think is jyp purposely mistreating her by not letting her participate in writing songs for the group but the reality is that the staff send the instrumental of a song to a group chat and the one that respond faster in tasked with writing the lyrics, the others are simply more attentive to that kind of work and tzuyu isnt. Something similar could be happening, except for brands that directly choose 1 of the twice girls the rest of endorsements are distributed by who respond first.
tzuyu is one of the most popular members in twice, and for sure lot of brands want her but she has to fight for her own career and honestly she doesnt look like that assertive type.