Kara-tur was created for Western players who were starting to know more about Asian cultures, and the manga had just arrived to Western market.
If you want names and places, you can find it in the Forgotten Realms wiki. Until now almost all metaplot is frozen, stopped or paralyzed. If you want isekai and jianghu, you cand find free manga+manghua+manghwa in internet. Also you could recycle the lore of the RPG "Legends of the five Rings". Even this has got a 5ed adaptation. There are also sourcebooks about Kara-Tur in DMGuild because technically they are within Forgotten Realms. A new unlocking is not necessary.
Other point if is there are plans about a future update of martial adepts(crusader, warblade and swordsage) then D&D jianghu should be designed to allow space for these classes. Or the incarnum game mechanic could be recycled for a new class: the cultivator, based in the xianxia fiction.
* Hasbro has acquired some Japanese IP in the past. It could happen again. A Japanese company could create a new-brand isekai D&D setting with the intention to be acquired by Hasbro.
* Chinese market is too risky and complicated. Even if a Chinese 3PP created from zero a D&D xuanhuan setting for Chinese market and also to be introduced into the Western market to promote the soft power, this could be parodied by Koreans, Japaneses and people from other countries, for example the antagonist would be an invasion of the formians. And let's pray for no more troubles about Taiwan!
