I mean, availability is determined by the operating airline. It's completely normal that Flying Blue will have the best routing options and availibility on AF/KLM or its JV parteniares KE and MU. It's geared towards European customers who would fly from western or central Europe to China.

I'm not very sure about the frequencies of TPAC post-Covid but I read that demand is high and flights are scarces. So if those airlines feel they can sell those seats to cash-paying customers, they see no need to offer any availability to FB members.